Colorado organized as a United States territory

Background. The Pike's Peak gold rush began in July 1858, drawing prospectors to the Pike's Peak Country of western Kansas Territory and southwestern Nebraska Territory. Rapid population growth from this boom led to the creation of the Colorado Territory. The State of Kansas was created on January 29, 1861, formalizing the separation of the western portion of the now defunct Kansas Territory, and the gold rush lasted until the territory's creation on February 28, 1861.

Legislative Organization. Colorado Territory was officially organized by Act of Congress on February 28, 1861 (12 Stat. 172). The territory was formed out of lands previously part of the Kansas, Nebraska, Utah, and New Mexico territories. This act established the Territory of Colorado as an organized incorporated territory of the United States, existing until statehood in 1876.

Local Context. While the act was federal, Denver City was a notable settlement in the new territory. Denver City residents had donated 53 lots in May 1859 to secure the region's first overland wagon route, and the Denver City, Kansas Territory, post office opened on February 11, 1860. Denver City itself was not incorporated until November 7, 1861, and did not become the territorial capital until December 9, 1867.