Editing Colorado (section)

===Territory act===
{{Main|Organic act#List of organic acts|New Mexico Territory|Utah Territory|Kansas–Nebraska Act|Kansas Territory|Nebraska Territory|Colorado Territory|Pike's Peak Gold Rush}}
[[File:1860 Colorado Territory map.svg|thumb|left|The territories of [[New Mexico Territory|New Mexico]], [[Utah Territory|Utah]], [[Kansas Territory|Kansas]], and [[Nebraska Territory|Nebraska]] before the creation of the [[Territory of Colorado]]]]

Thirty days later on February 28, 1861, outgoing U.S. President [[James Buchanan]] signed an Act of Congress organizing the [[Free state (United States)|free]] [[Territory of Colorado]].<ref name=ColoradoOrganicAct/> 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 ''[[:es:Rio Colorado|el Rio Colorado]]'' for the red-brown silt that the river carried from the mountains.<ref>{{cite web |last1=Multiple Property Documentation Form |title=National-Register-of-Historic |url=https://www.nps.gov/elca/learn/historyculture/upload/National-Register-of-Historic-Places-Multiple-Properties-508.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://www.nps.gov/elca/learn/historyculture/upload/National-Register-of-Historic-Places-Multiple-Properties-508.pdf |archive-date=2022-10-09 |url-status=live |website=www.nps.gov}}</ref>{{failed verification|date=April 2021}} In 1859, a U.S. Army [[Topography|topographic]] expedition led by Captain [[John Navarre Macomb, Jr.|John Macomb]] located the confluence of the [[Green River (Colorado River)|Green River]] with the [[Grand River (Colorado)|Grand River]] in what is now [[Canyonlands National Park]] in [[Utah]].<ref name=Macomb>Report of the exploring expedition from Santa Fé, New Mexico, to the junction of the Grand and Green Rivers of the great Colorado of the West, in 1859: under the command of Capt. J. N. Macomb, Corps of topographical engineers, Volume 1 [https://archive.org/stream/reportofexplorin00unitrich#page/n5/mode/2up @ archive.org]</ref> 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 [[Confederate States of America|Confederacy]], the vast majority remained fiercely loyal to the [[Union (American Civil War)|Union]] cause.

In 1862, a force of Texas cavalry invaded the [[Territory of New Mexico]] and captured [[Santa Fe, New Mexico|Santa Fe]] on March 10. The object of this [[New Mexico Campaign|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 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.<ref>{{Cite book |title=Blood & treasure : Confederate Empire in the Southwest|last=Frazier |first=Donald Shaw |date=1995|publisher=Texas A & M University Press|isbn=0585303304|edition=1st|location=College Station|oclc=45732362}}</ref> 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 the Southwestern United States.
[[File:Mount of the Holy Cross.jpeg|thumb|[[Mount of the Holy Cross]], photographed by [[William Henry Jackson]] in 1874]]

In 1864, [[Governor of Colorado|Territorial Governor]] [[John Evans (Colorado 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 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 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, Colorado|Julesburg]], in the northeast corner of 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 the [[Ute tribe|Ute Indian]] reservation in southwestern Colorado. The Ute people were removed from the San Juan Mountains the following year.