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Greenhorn Limestone

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The Greenhorn Limestone or Greenhorn Formation is a geologic formation in the Great Plains Region of the United States, dating to the Cenomanian and Turonian ages of the Late Cretaceous period. The formation gives its name to the Greenhorn cycle of the Western Interior Seaway .

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126-714: The formation was named for the Greenhorn Station on Greenhorn Creek in Colorado in 1896 by Grove Karl Gilbert ; and it is the namesake of the Greenhorn Marine Cycle of the Cretaceous Western Interior Seaway . With the underlying Graneros Shale and Dakota Formation , it records the progressive stage of Greenhorn Marine Cycle while the overlying Carlile Shale records the regressive stage. The Greenhorn unit name

252-720: A gunman killed 10 people , including a police officer, in a King Soopers supermarket in Boulder . In an instance of anti-LGBT violence , a gunman killed 5 people at a nightclub in Colorado Springs during the night of November 19–20, 2022. Four warships of the U.S. Navy have been named the USS Colorado . The first USS Colorado was named for the Colorado River and served in the Civil War and later

378-623: A fauna resembling its position in the dry deserts with temperature extremes. The western continental coast of the U.S., just as the East Coast, varies from a colder-to-warmer climate from north to south. Few species live throughout the entire West Coast, however, there are some, including the bald eagle that inhabits both the Alaskan Aleutian Islands and the California Channel Islands . In most of

504-676: A major industry in Colorado. This period became known locally as the Carnation Gold Rush . Poor labor conditions and discontent among miners resulted in several major clashes between strikers and the Colorado National Guard , including the 1903–1904 Western Federation of Miners Strike and Colorado Coalfield War , the latter of which included the Ludlow massacre that killed a dozen women and children. Both

630-414: A myth of the west which has shaped much of American popular culture since the late 19th century. Writers as diverse as Bret Harte and Zane Grey celebrated or derided cowboy culture, while artists such as Frederic Remington created western art as a method of recording the expansion into the west. The American cinema , in particular, created the genre of the western movie , which, in many cases, use

756-884: A national issue, agencies of the federal government own and manage vast areas of land. (The most important among these are the National Park Service and the Bureau of Land Management within the Interior Department , and the U.S. Forest Service within the Agriculture Department .) National parks are reserved for recreational activities such as fishing , camping , hiking , and boating , but other government lands also allow commercial activities like ranching , logging , and mining . In recent years, some local residents who earn their livelihoods on federal land have come into conflict with

882-653: A rapid decline in the organization's power, with membership waning significantly by the end of the 1920s. Colorado became the first western state to host a major political convention when the Democratic Party met in Denver in 1908. By the U.S. census in 1930 , the population of Colorado first exceeded one million residents. Colorado suffered greatly through the Great Depression and the Dust Bowl of

1008-578: A sharp decline in citrus production in Arizona. Many varieties of chile peppers are grown in the valleys of New Mexico . Starting in 1902, Congress passed a series of acts authorizing the establishment of the United States Bureau of Reclamation to oversee water development projects in seventeen western states. During the first half of the 20th century, dams and irrigation projects provided water for rapid agricultural growth throughout

1134-648: A significant portion of the extreme weather occurs in the least populated areas of the state. Thunderstorms are common east of the Continental Divide in the spring and summer, yet are usually brief. Hail is a common sight in the mountains east of the Divide and across the eastern Plains, especially the northeast part of the state. Hail is the most commonly reported warm-season severe weather hazard, and occasionally causes human injuries, as well as significant property damage. The eastern Plains are subject to some of

1260-464: A total 2020 population of 78,588,572. The West is one of the most sparsely settled areas in the United States with 49.5 inhabitants per square mile (19.1 inhabitants/km ). Only Texas with 78.0 inhabitants/sq mi (30.1 inhabitants/km ), Washington with 86.0 inhabitants/sq mi (33.2 inhabitants/km ), and California with 213.4 inhabitants/sq mi (82.4 inhabitants/km ) exceed

1386-754: A volcano in Washington , is also over 14,000 feet (4,300 m). Mount St. Helens , a volcano in the Cascades , erupted explosively in 1980 . A major volcanic eruption at Mount Mazama around 4860 BC formed Crater Lake . These mountain ranges see heavy precipitation, capturing most of the moisture that remains after the Coast Ranges, and creating a rain shadow to the east forming vast stretches of arid land. These dry areas encompass much of Nevada , Utah , and Arizona . The Mojave Desert and Sonoran Desert along with other deserts are found here. Beyond

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1512-519: Is a mix of high plains, foothills, and mountains. Northwest and west Colorado are predominantly mountainous, with some desert lands mixed in. Southwest and southern Colorado are a complex mixture of desert and mountain areas. The climate of the Eastern Plains is semi-arid ( Köppen climate classification : BSk ) with low humidity and moderate precipitation, usually from 15 to 25 inches (380 to 640 millimeters) annually, although many areas near

1638-841: Is drained by the Colorado River. The South Park of Colorado is the region of the headwaters of the South Platte River. In south-central Colorado is the large San Luis Valley , where the headwaters of the Rio Grande are located. The northern part of the valley is the San Luis Closed Basin , an endorheic basin that helped created the Great Sand Dunes . The valley sits between the Sangre de Cristo Mountains and San Juan Mountains . The Rio Grande drains due south into New Mexico, Texas, and Mexico. Across

1764-688: Is flat and rolling land. East of the Rocky Mountains is the Colorado Eastern Plains of the High Plains , the section of the Great Plains within Colorado at elevations ranging from roughly 3,350 to 7,500 feet (1,020 to 2,290 m). The Colorado plains are mostly prairies but also include deciduous forests , buttes , and canyons. Precipitation averages 15 to 25 inches (380 to 640 mm) annually. Eastern Colorado

1890-544: Is generally accessed through artesian wells . Heavy usage of these wells for irrigation purposes caused underground water reserves to decline in the region. Eastern Colorado also hosts a considerable amount and range of livestock, such as cattle ranches and hog farms. Roughly 70% of Colorado's population resides along the eastern edge of the Rocky Mountains in the Front Range Urban Corridor between Cheyenne, Wyoming , and Pueblo, Colorado . This region

2016-773: Is higher than the high elevation points of 18 states and the District of Columbia. The Continental Divide of the Americas extends along the crest of the Rocky Mountains. The area of Colorado to the west of the Continental Divide is called the Western Slope of Colorado . West of the Continental Divide, water flows to the southwest via the Colorado River and the Green River towards the Gulf of California . Within

2142-540: Is in the Western states. Public lands account for 25 to 75 percent of the total land area in these states. The climate of the West is semi-arid , yet parts of the region get high amounts of rain or snow. Other parts are true desert which receive less than 5 inches (130 mm) of rain per year. The climate is increasingly unstable, and subject to periods of severe drought. The seasonal temperatures vary greatly throughout

2268-535: Is known as "The Western Slope") are the cities of Grand Junction , Durango , and Montrose . Download coordinates as: To the west of the Great Plains of Colorado rises the eastern slope of the Rocky Mountains . Notable peaks of the Rocky Mountains include Longs Peak , Mount Blue Sky , Pikes Peak , and the Spanish Peaks near Walsenburg , in southern Colorado. This area drains to the east and

2394-466: Is more complex than states outside of the Mountain States region. Unlike most other states, southern Colorado is not always warmer than northern Colorado. Most of Colorado is made up of mountains, foothills, high plains, and desert lands. Mountains and surrounding valleys greatly affect the local climate. Northeast, east, and southeast Colorado are mostly the high plains, while Northern Colorado

2520-409: Is no wonder that the region is difficult to define precisely. Sensing a possible shift in the popular understanding of the West as a region in the early 1990s, historian Walter Nugent conducted a survey of three groups of professionals with ties to the region: a large group of Western historians (187 respondents), and two smaller groups, 25 journalists and publishers and 39 Western authors. A majority of

2646-522: Is partially protected from prevailing storms that blow in from the Pacific Ocean region by the high Rockies in the middle of Colorado. The "Front Range" includes Denver, Boulder , Fort Collins , Loveland, Castle Rock , Colorado Springs, Pueblo, Greeley, and other townships and municipalities in between. On the other side of the Rockies, the significant population centers in western Colorado (which

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2772-689: Is predicted to experience drought-like conditions for much of the 21st century. Violent thunderstorms occur east of the Rockies . Tornadoes occur every spring on the southern plains, with the most common and most destructive centered on Tornado Alley , which covers eastern portions of the West, ( Texas to North Dakota ), and all states in between and to the east. Agriculture varies depending on rainfall, irrigation, soil, elevation, and temperature extremes. The arid regions generally support only livestock grazing, chiefly beef cattle. The wheat belt extends from Texas through The Dakotas , producing most of

2898-559: Is presently mainly farmland and rangeland, along with small farming villages and towns. Corn , wheat , hay , soybeans , and oats are all typical crops. Most villages and towns in this region boast both a water tower and a grain elevator . Irrigation water is available from both surface and subterranean sources. Surface water sources include the South Platte , the Arkansas River , and a few other streams. Subterranean water

3024-777: Is recognized in the Great Plains Region from Minnesota and Iowa to New Mexico to Montana and the Dakotas . In much of Alberta and Saskatchewan, the "Second White-Specked Shale" contains limy equivalents of the Greenhorn. In Kansas , the Greenhorn Formation is divided into the (lowest) Lincoln Limestone, Hartland Shale, Jetmore Chalk, and (highest) Pfeifer shale members, each noted by changes in chalkiness and limestone rhythmite patterns. In eastern Colorado and western Kansas Hydrocarbon exploration ,

3150-464: Is the highest point in Colorado and the Rocky Mountains of North America. Colorado is the only U.S. state that lies entirely above 1,000 meters elevation. The point where the Arikaree River flows out of Yuma County, Colorado , and into Cheyenne County, Kansas , is the lowest in Colorado at 3,317 feet (1,011 m) elevation. This point, which is the highest low elevation point of any state,

3276-568: Is today the State of Colorado has been inhabited by Native Americans and their Paleoamerican ancestors for at least 13,500 years and possibly more than 37,000 years. The eastern edge of the Rocky Mountains was a major migration route that was important to the spread of early peoples throughout the Americas. The Lindenmeier site in Larimer County contains artifacts dating from approximately 8720 BCE. The Ancient Pueblo peoples lived in

3402-432: Is very prone to droughts. Most of the precipitation comes from thunderstorms, which can be severe, and from major snowstorms that occur in the winter and early spring. Otherwise, winters tend to be mostly dry and cold. In much of the region, March is the snowiest month. April and May are normally the rainiest months, while April is the wettest month overall. The Front Range cities closer to the mountains tend to be warmer in

3528-644: The United States Census Bureau . As American settlement in the U.S. expanded westward , the meaning of the term the West changed. Before around 1800, the crest of the Appalachian Mountains was seen as the western frontier . The frontier moved westward and eventually the lands west of the Mississippi River were considered the West . The U.S. Census Bureau's definition of the 13 westernmost states includes

3654-578: The Adams-Onís Treaty of 1819. The treaty took effect on February 22, 1821. Having settled its border with Spain, the U.S. admitted the southeastern portion of the Territory of Missouri to the Union as the state of Missouri on August 10, 1821. The remainder of Missouri Territory, including what would become northeastern Colorado, became an unorganized territory and remained so for 33 years over

3780-593: The Asiatic Squadron , where it was attacked during the 1871 Korean Expedition . The later three ships were named in honor of the state, including an armored cruiser and the battleship USS Colorado , the latter of which was the lead ship of her class and served in World War II in the Pacific beginning in 1941. At the time of the attack on Pearl Harbor , the battleship USS Colorado was located at

3906-577: The Cenozoic era. Salt flats and salt lakes reveal a time when the great inland seas covered much of what is now the West. The Pacific states are the most geologically active areas in the United States. Earthquakes cause damage every few to several years in California . While the Pacific states are the most volcanically active areas, extinct volcanoes and lava flows are found throughout most of

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4032-590: The East . During the latter half of the 20th century, several transcontinental interstate highways crossed the West bringing more trade and tourists from the East. Oil boom towns in Texas and Oklahoma rivaled the old mining camps for their rawness and wealth. The Dust Bowl forced children of the original homesteaders even further west. The movies became America's chief entertainment source featuring western fiction , later

4158-739: The Fencepost limestone , from which the Kansas stone posts were quarried. The combination of the toughness of the Fencepost limestone with the softness of the chalk and shale above and below as resulted in the formation of the main range of the Smoky Hills north and west of Salina . In 2018, Kansas Legislation HB 2650 designated the Greenhorn Limestone formation, specifically "the famous "post rock" limestone" bed of that unit, to be

4284-540: The Four Corners region with Arizona , New Mexico , and Utah . It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas to the east, and Oklahoma to the southeast. Colorado is noted for its landscape of mountains , forests , high plains , mesas , canyons , plateaus , rivers , and desert lands. It encompasses most of the Southern Rocky Mountains , as well as

4410-580: The Grand Canyon . The Colorado River is a major source of water in the Southwest and many dams, such as the Hoover Dam , form reservoirs along it. So much water is drawn for drinking water throughout the West and irrigation in California that in most years, water from the Colorado River no longer reaches the Gulf of California . The Columbia River , the largest river in volume flowing into

4536-561: The Great Lakes region to hunt across the High Plains of Colorado and Wyoming . The Spanish Empire claimed Colorado as part of Nuevo México . The U.S. acquired the territorial claim to the eastern Rocky Mountains with the Louisiana Purchase from France in 1803. This U.S. claim conflicted with the claim by Spain to the upper Arkansas River Basin . In 1806, Zebulon Pike led a U.S. Army reconnaissance expedition into

4662-604: The Gulf of Mexico . The Mississippi River forms the easternmost possible boundary for the West today. The Missouri River , a tributary of the Mississippi , flows from its headwaters in the Rocky Mountains eastward across the Great Plains , a vast grassy plateau, before sloping gradually down to the forests and hence to the Mississippi . The Colorado River snakes through the Mountain states , at one point forming

4788-703: The Las Vegas Valley and Los Angeles . Plains make up much of the eastern portion of the West, underlain with sedimentary rock from the Upper Paleozoic , Mesozoic , and Cenozoic eras. The Rocky Mountains expose igneous and metamorphic rock both from the Precambrian and from the Phanerozoic eon. The Inter-mountain States and Pacific Northwest have huge expanses of volcanic rock from

4914-413: The Mississippi , Ohio , Missouri , Illinois , Tennessee , Cumberland , Arkansas , and White Rivers and their tributaries, and certain other rivers that flow towards the Gulf of Mexico ." The Ohio River portion of the system includes parts of several Atlantic coastal states, from Georgia to New York. Most of the public land held by the U.S. National Forest Service and Bureau of Land Management

5040-412: The Mormon Trail , made its fortunes on outfitting settlers; St. Louis built itself upon the vast fur trade in the West before its settlement. The 1850s were marked by political battles over the expansion of slavery into the western territories, issues leading to the Civil War . Between 1863 and 1869, North America's first transcontinental railroad was constructed to connect the eastern US with

5166-407: The Mountain States include Denver , Colorado Springs , Phoenix , Tucson , Albuquerque , Las Vegas , Reno , Salt Lake City , Boise , El Paso , and Billings . Along the Pacific Ocean coast lie the Coast Ranges , which, while not approaching the scale of the Rocky Mountains , are formidable nevertheless. They collect a large part of the airborne moisture moving in from the ocean. East of

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5292-466: The Northern Mariana Islands ) are sometimes considered part of the Western United States. American Samoa is in Polynesia in the South Pacific Ocean , while Guam and the Northern Mariana Islands are in the Mariana Islands in the western North Pacific Ocean . Guam and the Northern Mariana Islands have district courts within the 9th Circuit , which includes western states such as California and Nevada. (See District Court of Guam and District Court for

5418-537: The Northwest , the highest mountain ranges, including the Rocky Mountains , the Sierra Nevada , and the Cascade Range , numerous glaciers , and the western edge of the Great Plains . It also contains the majority of the desert areas located in the United States. The Mojave and the Great Basin deserts lie entirely within the Western region, along with parts of the Sonoran and Chihuahuan deserts (the latter extends significantly into Texas, while both extend into Mexico ). Given this expansive and diverse geography it

5544-522: The Oklahoma panhandle are typically considered to be the Southwest states. Meanwhile, the states of Montana, Idaho, Oregon, and Washington can be considered part of the Northwest or Pacific Northwest . The term West Coast is commonly used to refer to just California, Oregon, Washington, and Alaska, whereas Hawaii is more geographically isolated from the continental U.S. and does not necessarily fit in any of these subregions . The three inhabited Pacific U.S. territories ( American Samoa , Guam and

5670-443: The Pacific Ocean from North America , and its tributary, the Snake River , water the Pacific Northwest. The Platte runs through Nebraska and was known for being a mile (2 km) wide but only a half-inch (1 cm) deep. The Rio Grande forms the border between Texas and Mexico before turning due north and splitting New Mexico in half. According to the United States Coast Guard , "The Western Rivers System consists of

5796-473: The Pacific coast . The resulting railroad connection revolutionized the settlement and economy of the American West by making the transportation of passengers and freight quicker, safer, and cheaper. The history of the American West in the late 19th and early 20th centuries has acquired a cultural mythos in the literature and cinema of the United States. The image of the cowboy , the homesteader , and westward expansion took real events and transmuted them into

5922-422: The Provisional Government of the Territory of Jefferson on August 24, 1859, but this new territory failed to secure approval from the Congress of the United States embroiled in the debate over slavery. The election of Abraham Lincoln for the President of the United States on November 6, 1860, led to the secession of nine southern slave states and the threat of civil war among the states . Seeking to augment

6048-471: The Rocky Mountains and the Great Basin to the Pacific Coast , and the mid-Pacific islands state, Hawaii. To the east of the Western United States is the Midwestern United States and the Southern United States , with Canada to the north and Mexico to the south. The West contains several major biomes , including arid and semi-arid plateaus and plains , particularly in the American Southwest ; forested mountains , including three major ranges,

6174-503: The Rocky Mountains was a major migration route for early peoples who spread throughout the Americas. In 1848, much of the Nuevo México region was annexed to the United States with the Treaty of Guadalupe Hidalgo . The Pike's Peak Gold Rush of 1858–1862 created an influx of settlers. On February 28, 1861, U.S. President James Buchanan signed an act creating the Territory of Colorado , and on August 1, 1876, President Ulysses S. Grant signed Proclamation 230 , admitting Colorado to

6300-513: The Sangre de Cristo Range to the east of the San Luis Valley lies the Wet Mountain Valley . These basins, particularly the San Luis Valley, lie along the Rio Grande rift , a major geological formation of the Rocky Mountains, and its branches. The Western Slope of Colorado includes the western face of the Rocky Mountains and all of the area to the western border. This area includes several terrains and climates from alpine mountains to arid deserts. The Western Slope includes many ski resort towns in

6426-423: The Sierra Nevada , the Cascades , and Rocky Mountains; the long coastal shoreline of the American Pacific Coast ; and the rainforests of the Pacific Northwest . The Western United States is the largest region of the country, covering nearly half the land area of the contiguous United States . It is also the most geographically diverse, incorporating geographic regions such as the temperate rainforests of

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6552-435: The Territory of New Mexico , and the Territory of Utah . On April 9, 1851, Hispano settlers from the area of Taos settled the village of San Luis , then in the New Mexico Territory , as Colorado's first permanent Euro-American settlement , further cementing the traditions of New Mexican cuisine and New Mexico music in the developing Southern Rocky Mountain Front . In 1854, Senator Stephen A. Douglas persuaded

6678-456: The U.S. Congress to divide the unorganized territory east of the Continental Divide into two new organized territories, the Territory of Kansas and the Territory of Nebraska , and an unorganized southern region known as the Indian Territory . Each new territory was to decide the fate of slavery within its boundaries, but this compromise merely served to fuel animosity between free soil and pro-slavery factions. The gold seekers organized

6804-428: The Union as the 38th state. The Spanish adjective "colorado" means "colored red" or "ruddy". Colorado is nicknamed the " Centennial State " because it became a state 100 years (and four weeks) after the signing of the United States Declaration of Independence . Denver is the capital, the most populous city , and the center of the Front Range Urban Corridor . Colorado Springs is the second most populous city of

6930-448: The Union cause. In 1862, a force of Texas cavalry invaded the Territory of New Mexico and captured Santa Fe on March 10. The object of this Western Campaign was to seize or disrupt Colorado and California's gold fields and seize Pacific Ocean ports for the Confederacy. A hastily organized force of Colorado volunteers force-marched from Denver City, Colorado Territory , to Glorieta Pass , New Mexico Territory, in an attempt to block

7056-432: The Ute Indian reservation in southwestern Colorado. The Ute people were removed from the San Juan Mountains the following year. The United States Congress passed an enabling act on March 3, 1875, specifying the requirements for the Territory of Colorado to become a state. On August 1, 1876 (four weeks after the Centennial of the United States ), U.S. President Ulysses S. Grant signed a proclamation admitting Colorado to

7182-446: The Virginia opossum , which occurs throughout California and coastal areas in Oregon and Washington. The North American beaver and mountain beaver live in forested areas of Washington, Oregon and Northern California. The kit fox lives throughout Arizona, New Mexico and Utah, while the gray fox occurs throughout the Western U.S. The Western United States has been populated by Native Americans since at least 11,000 years ago, when

7308-417: The free Territory of Colorado . The original boundaries of Colorado remain unchanged except for government survey amendments. In 1776, Spanish priest Silvestre Vélez de Escalante recorded that Native Americans in the area knew the river as el Rio Colorado for the red-brown silt that the river carried from the mountains. In 1859, a U.S. Army topographic expedition led by Captain John Macomb located

7434-404: The question of slavery . After 11 years of war, Spain finally recognized the independence of Mexico with the Treaty of Córdoba signed on August 24, 1821. Mexico eventually ratified the Adams–Onís Treaty in 1831. The Texian Revolt of 1835–36 fomented a dispute between the U.S. and Mexico which eventually erupted into the Mexican–American War in 1846. Mexico surrendered its northern territory to

7560-427: The 1913–1914 Coalfield War and the Denver streetcar strike of 1920 resulted in federal troops intervening to end the violence. In 1927, the 1927-28 Colorado coal strike occurred and was ultimately successful in winning a dollar a day increase in wages. During it however the Columbine Mine massacre resulted in six dead strikers following a confrontation with Colorado Rangers . In a separate incident in Trinidad

7686-404: The 1930s, but a major wave of immigration following World War II boosted Colorado's fortune. Tourism became a mainstay of the state economy, and high technology became an important economic engine. The United States Census Bureau estimated that the population of Colorado exceeded five million in 2009. On September 11, 1957, a plutonium fire occurred at the Rocky Flats Plant , which resulted in

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7812-433: The Coast Ranges lie several cultivated fertile valleys , notably the San Joaquin and Sacramento valleys of California and the Willamette Valley of Oregon . Beyond the valleys lie the Sierra Nevada in the south and the Cascade Range in the north. Mount Whitney , at 14,505 feet (4,421 m) the tallest peak in the contiguous 48 states, is in the Sierra Nevada . The Cascades are also volcanic. Mount Rainier ,

7938-399: The Green River briefly crosses over into Colorado. The Western Slope of Colorado is drained by the Colorado River and its tributaries (primarily the Gunnison River , Green River , and the San Juan River ). The Colorado River flows through Glenwood Canyon , and then through an arid valley made up of desert from Rifle to Parachute , through the desert canyon of De Beque Canyon , and into

8064-568: The Greenhorn and other names replaced), several of which are consistent and widespread marker beds . These orange seams in the weathered shale and the yellow/orange stainings of some of the weathered limestones in the Greenhorn are associated with volcanic events in the Sevier orogeny . The oceanic iron (Fe) and volcanic sulfur (S) that precipitated with the volcanic ash into the calcareous mud (CaCO 3 ) formed pyrite (FeS 2 ), which later altered to selenite (CaSO 4 ·2H 2 O), siderite (FeCO 3 ), and limonite (FeO(OH)·nH 2 O), leading to

8190-427: The Northern Mariana Islands ). American Samoa, Guam, and the Northern Mariana Islands are also considered part of the western U.S. by the U.S. National Park Service , the Federal Reserve Bank system, FEMA , and the USGS . The population distribution by race in the Western United States (2022): As defined by the United States Census Bureau , the Western region of the United States includes 13 states, with

8316-516: The Pacific Coast where it increases again. In fact, the greatest annual rainfall in the United States falls in the coastal regions of the Pacific Northwest . Drought is much more common in the West than the rest of the United States. The driest place recorded in the U.S. is Death Valley , California. In Western states, drought is closely associated with fire risk, and there have been a number of notable wildfires causing extensive property damage and wildlife habitat destruction . The Western United States

8442-402: The Rockies , 54 of which are over 14,000 feet (4,300 m), are found in central and western Colorado . East of the Rocky Mountains is the Great Plains, the western portions (for example, the eastern half of Colorado) of which are generally considered to be part of the western United States. The West has several long rivers that empty into the Pacific Ocean , while the eastern rivers run into

8568-409: The Rocky Mountains and towns west to Utah. It is less populous than the Front Range but includes a large number of national parks and monuments. The northwestern corner of Colorado is a sparsely populated region, and it contains part of the noted Dinosaur National Monument , which not only is a paleontological area, but is also a scenic area of rocky hills, canyons, arid desert, and streambeds. Here,

8694-527: The Southwestern United States. In 1864, Territorial Governor John Evans appointed the Reverend John Chivington as Colonel of the Colorado Volunteers with orders to protect white settlers from Cheyenne and Arapaho warriors who were accused of stealing cattle. Colonel Chivington ordered his troops to attack a band of Cheyenne and Arapaho encamped along Sand Creek. Chivington reported that his troops killed more than 500 warriors. The militia returned to Denver City in triumph, but several officers reported that

8820-421: The Territory. The Union Pacific linked up with the Central Pacific Railroad at Promontory Summit, Utah , on May 10, 1869, to form the First transcontinental railroad . The Denver Pacific Railway reached Denver in June of the following year, and the Kansas Pacific arrived two months later to forge the second line across the continent. In 1872, rich veins of silver were discovered in the San Juan Mountains on

8946-466: The Texans. On March 28, the Coloradans and local New Mexico volunteers stopped the Texans at the Battle of Glorieta Pass , destroyed their cannon and supply wagons, and dispersed 500 of their horses and mules. The Texans were forced to retreat to Santa Fe. Having lost the supplies for their campaign and finding little support in New Mexico, the Texans abandoned Santa Fe and returned to San Antonio in defeat. The Confederacy made no further attempts to seize

9072-645: The U.S. with the Treaty of Guadalupe Hidalgo after the war in 1848; this included much of the western and southern areas of Colorado. Most American settlers first traveled to Colorado through the Santa Fe Trail , which connected the U.S. to Santa Fe and the Camino Real de Tierra Adentro southward. Others were traveling overland west to the Oregon Country , the new goldfields of California , or

9198-470: The Union as the 38th state and earning it the moniker "Centennial State". The discovery of a major silver lode near Leadville in 1878 triggered the Colorado Silver Boom . The Sherman Silver Purchase Act of 1890 invigorated silver mining, and Colorado's last, but greatest, gold strike at Cripple Creek a few months later lured a new generation of gold seekers. Colorado women were granted

9324-492: The West and California , whites and blacks together are less than half the population because of the preference for the region by Hispanics and Asians . African and European Americans, however, continue to wield a stronger political influence because of the lower rates of citizenship and voting among Asians and Hispanics . According to 2022 estimates from the Census Bureau, the largest ancestries reported in

9450-496: The West and brought prosperity for several states, where agriculture had previously only been subsistence level. Following World War II , the West's cities experienced an economic and population boom. The population growth, mostly in the Southwest states of New Mexico , Utah , Colorado , Arizona , and Nevada , has strained water and power resources, with water diverted from agricultural uses to major population centers, such as

9576-581: The West are Mexican (24.2%), German (10.1%), English (9.5%), Irish (7.2%), Italian (3.5%), Filipino (3.4%), and Chinese (3.3%). The West also contains much of the Native American population in the U.S., particularly in the large reservations in the Mountain and Desert States . As of 2022, the West is home to 365,351 Navajo , 109,208 Apache , and 78,364 Blackfeet , as well as 276,082 people identifying as Indigenous Mexican . The largest concentrations for African-Americans in

9702-509: The West as a metaphor for the virtue of self-reliance and an American ethos. The contrast between the romanticism of culture about the West and the actuality of the history of the westward expansion has been a theme of late 20th and early 21st century scholarship about the West. Cowboy culture has become embedded in the American experience as a common cultural touchstone, and modern forms as diverse as country and western music have celebrated

9828-465: The West can be found in San Diego , Los Angeles , Oakland , Sacramento , Fresno , San Francisco , Seattle , Tacoma , Phoenix , Las Vegas , Denver , and Colorado Springs . The Western United States has a higher sex ratio (more males than females ) than any other region in the United States. Because the tide of development had not yet reached most of the West when conservation became

9954-982: The West. The ecoregions and ecology found in the Western United States are extremely varied. For instance, large areas of land are made up of everything from sand dunes in the Central Basin and Range ecoregion , which makes up much of the State of Nevada , to the ecology of the North Cascades in Washington state , which has the largest concentration of active alpine glaciers in the lower 48 . The densely forested areas found in Northern California , Oregon , Washington, Idaho , and Montana have mostly species adapted to living in temperate climates , while Southern California , Nevada , Arizona , southern Utah , and New Mexico have

10080-502: The West. Low elevations on the West Coast have warm summers and mild winters with little to no snow. The desert southwest has very hot summers and mild winters. While the mountains in the southwest receive generally large amounts of snow. The Inland Northwest has a continental climate of warm to hot summers and cold to bitterly cold winters. Annual rainfall is greater in the eastern portions, gradually tapering off until reaching

10206-802: The Western Slope can be found at Colorado Mesa University in Grand Junction, Western Colorado University in Gunnison, Fort Lewis College in Durango, and Colorado Mountain College in Glenwood Springs and Steamboat Springs. The Four Corners Monument in the southwest corner of Colorado marks the common boundary of Colorado, New Mexico , Arizona , and Utah ; the only such place in the United States. The climate of Colorado

10332-509: The Western Slope. Grand Junction and Durango are the only major centers of television broadcasting west of the Continental Divide in Colorado, though most mountain resort communities publish daily newspapers. Grand Junction is located at the juncture of Interstate 70 and US 50, the only major highways in western Colorado. Grand Junction is also along the major railroad of the Western Slope, the Union Pacific . This railroad also provides

10458-626: The alpine snow melts by mid-August except for a few snow-capped peaks and a few small glaciers. The Colorado Mineral Belt , stretching from the San Juan Mountains in the southwest to Boulder and Central City on the front range, contains most of the historic gold- and silver-mining districts of Colorado. The 30 highest major summits of the Rocky Mountains of North America are all within the state. The summit of Mount Elbert at 14,437.6 feet (4,400.58 m) elevation in Lake County

10584-596: The arid desert of Grand Valley , where the city of Grand Junction is located. Also prominent is the Grand Mesa , which lies to the southeast of Grand Junction; the high San Juan Mountains, a rugged mountain range; and to the north and west of the San Juan Mountains, the Colorado Plateau . Grand Junction, Colorado , at the confluence of the Colorado and Gunnison Rivers, is the largest city on

10710-714: The biggest hail storms in North America. Notable examples are the severe hailstorms that hit Denver on July 11, 1990, and May 8, 2017, the latter being the costliest ever in the state. Western United States The Western United States (also called the American West , the Western States , the Far West , the Western territories , and the West ) is one of the four census regions defined by

10836-502: The boundaries of the new Territory of Colorado exclusively by lines of latitude and longitude , stretching from 37°N to 41°N latitude, and from 102°02′48″W to 109°02′48″W longitude ( 25°W to 32°W from the Washington Meridian ). After 163 years of government surveys, the borders of Colorado were officially defined by 697 boundary markers and 697 straight boundary lines . Colorado, Wyoming , and Utah are

10962-653: The community of Hollywood in Los Angeles became the headquarters of the mass media such as radio and television production. California has emerged as the most populous state and one of the top 10 economies in the world. Massive late 19th–20th century population and settlement booms created two megalopolis areas of the Greater Los Angeles / Southern California and the San Francisco Bay Area / Northern California regions, one of

11088-649: The confluence of the Green River with the Grand River in what is now Canyonlands National Park in Utah . The Macomb party designated the confluence as the source of the Colorado River. On April 12, 1861, South Carolina artillery opened fire on Fort Sumter to start the American Civil War . While many gold seekers held sympathies for the Confederacy , the vast majority remained fiercely loyal to

11214-586: The contiguous Western U.S. are mule deer , white-tailed antelope squirrels , cougars , American badgers , coyotes , hawks and several species of snakes and lizards are common. While the American black bear lives throughout the U.S., the brown bears and grizzly bears are more common in the northwest and in Alaska. Along the West Coast there are several species of whales, sea otters , California sea lions , eared seals and northern elephant seals . In

11340-626: The deserts lie the Rocky Mountains . In the north, they run almost immediately east of the Cascade Range , so that the desert region is only a few miles wide by the time one reaches the Canada–US border. The Rockies are hundreds of miles wide and run uninterrupted from New Mexico to Alaska . The Rocky Mountain Region is the highest overall area of the United States, with an average elevation of above 4,000 feet (1,200 m). The tallest peaks of

11466-473: The disputed region. Colonel Pike and his troops were arrested by Spanish cavalrymen in the San Luis Valley the following February, taken to Chihuahua , and expelled from Mexico the following July. The U.S. relinquished its claim to all land south and west of the Arkansas River and south of 42nd parallel north and west of the 100th meridian west as part of its purchase of Florida from Spain with

11592-441: The divisions are Lincoln Limestone, Hartford Shale, and Bridge Creek Limestone. In other states, where the formation is less developed, the unit is not subdivided and is named the Greenhorn Limestone, as a formation or as a member of another formation, e.g., Cody Shale , Colorado Shale , and Mancos Shale . Within Kansas and a small neighboring portion of Nebraska, the Greenhorn Formation is particularly noted for its uppermost bed,

11718-513: The dry, inland desert areas of states such as California, Nevada, Arizona and New Mexico there are some of the world's most venomous lizards, snakes and scorpions. The most notorious might be the Gila monster and Mohave rattlesnake , both found in deserts in the Southwest . The Sonoran Desert has eleven species of rattlesnakes - more than anywhere else in the world. Along the southwestern border there are jaguars and ocelots . Other mammals include

11844-539: The entire Great Basin and all lands drained by the rivers Green , Grand , and Colorado . The federal government of the U.S. flatly refused to recognize the new Mormon government because it was theocratic and sanctioned plural marriage . Instead, the Compromise of 1850 divided the Mexican Cession and the northwestern claims of Texas into a new state and two new territories, the state of California ,

11970-607: The first Paleo-Indians arrived. Pre-Columbian trade routes to kingdoms and empires such as the Mound Builders existed in places such as Yellowstone National Park since around 1000 AD. Major settlement of the western territories developed rapidly in the 1840s, largely through the Oregon Trail and the California Gold Rush of 1849. California experienced such a rapid growth in a few short months that it

12096-497: The formation; such remains are presumed washed into the sea by rivers swollen by the heavy rainfalls of the hothouse Cretaceous. Colorado Colorado ( / ˌ k ɒ l ə ˈ r æ d oʊ , - ˈ r ɑː d oʊ / KOL -ə- RAD -oh, -⁠ RAH -doh , other variants; Spanish: [koloˈɾaðo] ) is a state in the Western United States . It is one of the Mountain states , sharing

12222-532: The historian respondents placed the eastern boundary of the West east of the Census definition out on the eastern edge of the Great Plains or on the Mississippi River . The survey respondents as a whole showed just how little agreement there was on the boundaries of the West. The region is split into two smaller units or divisions, by the U.S. Census Bureau: Other classifications distinguish between Southwest and Northwest . Arizona, New Mexico, West Texas , and

12348-483: The infamous Columbine High School massacre in 1999 which made international news, where two gunmen killed 12 students and one teacher, before committing suicide. The incident has spawned many copycat incidents . On July 20, 2012, a gunman killed 12 people in a movie theater in Aurora . The state responded with tighter restrictions on firearms, including introducing a limit on magazine capacity. On March 22, 2021,

12474-587: The interior of the Rocky Mountains are several large parks which are high broad basins. In the north, on the east side of the Continental Divide is the North Park of Colorado . The North Park is drained by the North Platte River , which flows north into Wyoming and Nebraska. Just to the south of North Park, but on the western side of the Continental Divide, is the Middle Park of Colorado , which

12600-433: The land's managers, who are required to keep land use within environmentally acceptable limits. The largest city in the region is Los Angeles , located on the West Coast . Other West Coast cities include San Diego , San Bernardino , San Jose , San Francisco , Oakland , Bakersfield , Fresno , Sacramento , Seattle , Tacoma , Anchorage , and Portland – some of which are dozens of miles inland. Prominent cities in

12726-628: The local and state Democrat and Republican parties , particularly in the governor's office and city governments of Denver, Cañon City , and Durango . A particularly strong element of the Klan controlled the Denver Police . Cross burnings became semi-regular occurrences in cities such as Florence and Pueblo. The Klan targeted African-Americans, Catholics , Eastern European immigrants, and other non-White Protestant groups. Efforts by non-Klan lawmen and lawyers including Philip Van Cise led to

12852-700: The mayor was accused of deputizing members of the KKK against the striking workers. More than 5,000 Colorado miners—many immigrants—are estimated to have died in accidents since records were first formally collected following an 1884 accident in Crested Butte that killed 59. In 1924, the Ku Klux Klan Colorado Realm achieved dominance in Colorado politics. With peak membership levels, the Second Klan levied significant control over both

12978-560: The midst and aftermath of the Civil War, many discouraged prospectors returned to their homes, but a few stayed and developed mines, mills, farms, ranches, roads, and towns in Colorado Territory. On September 14, 1864, James Huff discovered silver near Argentine Pass , the first of many silver strikes. In 1867, the Union Pacific Railroad laid its tracks west to Weir, now Julesburg , in the northeast corner of

13104-579: The national average of 77.98 inhabitants/sq mi (30.11 inhabitants/km ). As of 2022, just under half of the 78.7 million residents of the West live in California . The entire Western region has also been strongly influenced by European , Hispanic or Latino , Asian and Native Americans ; it contains the largest number of minorities in the U.S. While most of the studies of racial dynamics in America such as riots in Los Angeles have been written about European and African-Americans , in many cities in

13230-531: The naval base in San Diego, California, and thus went unscathed. The most recent vessel to bear the name USS Colorado is Virginia-class submarine USS Colorado (SSN-788) , which was commissioned in 2018. Colorado is notable for its diverse geography, which includes alpine mountains, high plains, deserts with huge sand dunes, and deep canyons. In 1861, the United States Congress defined

13356-850: The new Mormon settlements of the State of Deseret in the Salt Lake Valley , avoided the rugged Southern Rocky Mountains , and instead followed the North Platte River and Sweetwater River to South Pass (Wyoming) , the lowest crossing of the Continental Divide between the Southern Rocky Mountains and the Central Rocky Mountains. In 1849, the Mormons of the Salt Lake Valley organized the extralegal State of Deseret , claiming

13482-478: The northeastern portion of the Colorado Plateau and the western edge of the Great Plains . Colorado is the eighth most extensive and 21st most populous U.S. state. The United States Census Bureau estimated the population of Colorado at 5,877,610 as of July 1, 2023, a 1.80% increase since the 2020 United States census. The region has been inhabited by Native Americans and their ancestors for at least 13,500 years and possibly much longer. The eastern edge of

13608-482: The only states that have their borders defined solely by straight boundary lines with no natural features. The southwest corner of Colorado is the Four Corners Monument at 36°59′56″N , 109°2′43″W . The Four Corners Monument , located at the place where Colorado, New Mexico , Arizona , and Utah meet, is the only place in the United States where four states meet. Approximately half of Colorado

13734-620: The plains and into the foothills, there is a wide variety of climate types. Locations merely a few miles apart can experience entirely different weather depending on the topography. Most valleys have a semi-arid climate, not unlike the eastern plains, which transitions to an alpine climate at the highest elevations. Microclimates also exist in local areas that run nearly the entire spectrum of climates, including subtropical highland ( Cfb/Cwb ), humid subtropical ( Cfa ), humid continental ( Dfa/Dfb ), Mediterranean ( Csa/Csb ) and subarctic ( Dfc ). Extreme weather changes are common in Colorado, although

13860-628: The political power of the Union states , the Republican Party -dominated Congress quickly admitted the eastern portion of the Territory of Kansas into the Union as the free State of Kansas on January 29, 1861, leaving the western portion of the Kansas Territory, and its gold-mining areas, as unorganized territory. Thirty days later on February 28, 1861, outgoing U.S. President James Buchanan signed an Act of Congress organizing

13986-444: The population of Colorado resides, lies in a pronounced precipitation shadow as a result of being on the lee side of the Rocky Mountains. In summer, this area can have many days above 95 °F (35 °C) and often 100 °F (38 °C). On the plains, the winter lows usually range from 25 to −10 °F (−4 to −23 °C). About 75% of the precipitation falls within the growing season, from April to September, but this area

14112-494: The right to vote on November 7, 1893, making Colorado the second state to grant universal suffrage and the first one by a popular vote (of Colorado men). The repeal of the Sherman Silver Purchase Act in 1893 led to a staggering collapse of the mining and agricultural economy of Colorado, but the state slowly and steadily recovered. Between the 1880s and 1930s, Denver's floriculture industry developed into

14238-405: The rivers are semi-humid climate. The area is known for its abundant sunshine and cool, clear nights, which give this area a great average diurnal temperature range . The difference between the highs of the days and the lows of the nights can be considerable as warmth dissipates to space during clear nights, the heat radiation not being trapped by clouds. The Front Range urban corridor, where most of

14364-503: The sense of isolation and independence of spirit inspired by the frontiersmen on "virgin land". The advent of the automobile enabled the average American to tour the West. Western businessmen promoted Route 66 as a means to bring tourism and industry to the West. In the 1950s, representatives from all the western states built the Cowboy Hall of Fame and Western Heritage Center to showcase western culture and greet travelers from

14490-479: The significant plutonium contamination of surrounding populated areas. From the 1940s and 1970s, many protest movements gained momentum in Colorado, predominantly in Denver. This included the Chicano Movement , a civil rights , and social movement of Mexican Americans emphasizing a Chicano identity that is widely considered to have begun in Denver. The National Chicano Youth Liberation Conference

14616-483: The so-called battle was a blatant massacre of Indians at peace, that most of the dead were women and children, and that the bodies of the dead had been hideously mutilated and desecrated. Three U.S. Army inquiries condemned the action, and incoming President Andrew Johnson asked Governor Evans for his resignation, but none of the perpetrators was ever punished. This event is now known as the Sand Creek massacre . In

14742-584: The southeast, ultimately either via the Mississippi River or the Rio Grande into the Gulf of Mexico . The Rocky Mountains within Colorado contain 53 true peaks and 58 named peaks that are 14,000 feet (4,267 m) or higher in elevation above sea level, known as fourteeners . These mountains are largely covered with trees such as conifers and aspens up to the tree line , at an elevation of about 12,000 feet (3,658 m) in southern Colorado to about 10,500 feet (3,200 m) in northern Colorado. Above this tree line, only alpine vegetation grows. Much of

14868-471: The state rock of Kansas. The Greenhorn Formation is characterized as shale to chalky shale, light bluish-gray in color, with rhythmically repeating beds of chalk or limestone that become marly closer to the Rocky Mountains . The shale can weather to buff color under hilltops. Exposures show many thin, rust-colored bentonite beds (named for the Old Benton Limestone classification that

14994-456: The state. Residents of the state are known as Coloradans , although the antiquated "Coloradoan" is occasionally used. Major parts of the economy include government and defense, mining, agriculture , tourism, and increasingly other kinds of manufacturing. With increasing temperatures and decreasing water availability, Colorado's agriculture forestry, and tourism economies are expected to be heavily affected by climate change . The region that

15120-505: The tracks for Amtrak 's California Zephyr passenger train, which crosses the Rocky Mountains between Denver and Grand Junction. The Western Slope includes multiple notable destinations in the Colorado Rocky Mountains, including Glenwood Springs , with its resort hot springs, and the ski resorts of Aspen , Breckenridge , Vail , Crested Butte , Steamboat Springs , and Telluride . Higher education in and near

15246-712: The valleys and mesas of the Colorado Plateau in far southwestern Colorado. The Ute Nation inhabited the mountain valleys of the Southern Rocky Mountains and the Western Rocky Mountains , even as far east as the Front Range of the present day. The Apache and the Comanche also inhabited the Eastern and Southeastern parts of the state. In the 17th century, the Arapaho and Cheyenne moved west from

15372-534: The wheat and soybeans in the U.S. and exporting more to the rest of the world. Irrigation in the Southwest allows the growth of great quantities of fruits, nuts, and vegetables as well as grain, hay, and flowers. Texas is a major cattle and sheep raising area, as well as the nation's largest producer of cotton. Washington is famous for its apples, and Idaho for its potatoes. California and Arizona are major producers of citrus crops, however, declining supplies of water, as well as urban sprawl have contributed to

15498-467: The winter due to Chinook winds which warms the area, sometimes bringing temperatures of 70 °F (21 °C) or higher in the winter. The average July temperature is 55 °F (13 °C) in the morning and 90 °F (32 °C) in the afternoon. The average January temperature is 18 °F (−8 °C) in the morning and 48 °F (9 °C) in the afternoon, although variation between consecutive days can be 40 °F (22 °C). Just west of

15624-519: The yellow to orange staining. The formation is recognized for its sequence of index fossils , including oysters , Ammonoidea , Belemnitida , and Inoceramidae . The Greenhorn marine cycle was the deepest and broadest stage of the Western Interior Seaway, and supported large sharks and the largest of marine reptiles, including Mosasauridae and Pliosauroidea . Fossilized driftwood and dinosaur remains have been recovered from

15750-546: Was admitted to statehood in 1850 without the normal transitory phase of becoming an official territory. One of the largest migrations in American history occurred in the 1840s as the Latter Day Saints left the Midwest to build a theocracy in Utah . Both Omaha, Nebraska and St. Louis, Missouri laid claim to the title, "Gateway to the West" during this period. Omaha , home to the Union Pacific Railroad and

15876-490: Was held in Colorado in March 1969. In 1967, Colorado was the first state to loosen restrictions on abortion when governor John Love signed a law allowing abortions in cases of rape, incest, or threats to the woman's mental or physical health. Many states followed Colorado's lead in loosening abortion laws in the 1960s and 1970s. Since the late 1990s, Colorado has been the site of multiple major mass shootings , including

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