The Territory of Colorado was a historic, organized territory of the United States that existed between 1861 and 1876. Its boundaries were identical to the current State of Colorado. The territory ceased to exist when Colorado was admitted to the Union as a state on August 1, 1876. The territory was organized in the wake of the 1859 Pike's Peak Gold Rush, which had brought the first large concentration of white settlement to the region. The organic act creating the territory was passed by Congress and signed by President James Buchanan on February 28, 1861, during the secessions by Southern states that precipitated the American Civil War. The organization of the territory helped solidify Union control over a mineral rich area of the Rocky Mountains. Statehood was regarded as fairly imminent, but territorial ambitions for statehood were thwarted at the end of 1865 by a veto by President Andrew Johnson. Statehood for the territory was a recurring issue during the Ulysses Grant administration, with Grant advocating statehood against a less willing Congress during Reconstruction.

Description of the Colorado Territory
The land which ultimately became the Colorado Territory had first come under the jurisdiction of the United States under the 1803 Louisiana Purchase and the 1848 Mexican Cession.

History of the Colorado Territory
Originally, the lands that comprised the Colorado Territory were inhabited primarily by the Cheyenne and Arapaho on the Eastern Plains, and the Ute in the Rocky Mountains.
For more information on tribes of the Rocky Mountains and plains states, please see:
History of Colorado Historic Native American tribes

Indigenous populations
The earliest explorers of European extraction to visit the area were Spanish explorers such as Coronado, although the Coronado expedition of 1540-42 only skirted the future border of the Colorado Territory to the south and southeast. In 1776, Francisco Atanasio Domínguez and Silvestre Vélez de Escalante explored southern Colorado in the Dominguez-Escalante Expedition.
Other notable explorations included the Pike expedition of 1806-07 by Zebulon Pike, the journey along the north bank of the Platte River in 1820 by Stephen H. Long to what came to be called Longs Peak, the John C. Frémont expedition in 1845-46, and the Powell Geographic Expedition of 1869 by John Wesley Powell. u smell my name is bill

Exploration by non-native peoples
In 1779, Governor de Anza of New Mexico fought and defeated the Comanches under Cuerno Verde in southwestern Colorado. In 1786, de Anza made peace with the Comanches, creating an alliance against the Apaches.
A group of Cherokee crossed the South Platte and Cache la Poudre River valleys on their way to California in 1848 during the California Gold Rush. They reported finding trace amounts of gold in the South Platte and its tributaries as they passed along the mountains. In the south, in the Rio Grande valley, early Mexican families established themselves in large land grants (later contested by the U.S.) from the Mexican government.
In the early 18th century, the upper South Platte River valley had been infiltrated by fur traders, but had not been the site of permanent settlement. The first movement of permanent U.S. settlers in the area began with the Kansas-Nebraska Act of 1854, which allowed homestead land claims to be filed. Among the first settlers to establish claims were former fur traders who returned to the lands they once trapped, including Antoine Janis and other trappers from Fort Laramie who established a townsite near Laporte along the Cache la Poudre in 1858.
In 1858, Green Russell and a party of Georgians, having heard the story of the gold in the South Platte from Cherokee after they returned from California, set out to mine the area they described. That summer they founded a mining camp Auraria (named for a gold mining camp in Georgia) at the confluence of the South Platte and Cherry Creek. The Georgians left for their home state the following winter. At Bent's Fort along the Arkansas River, Russel told William Larimer, Jr., a Kansas land speculator, about the placer gold they had found. Larimer, realizing the opportunity to capitalize on it, hurried to Auraria. In November 1858, he laid claim to an arjadfjaslfjzsljfea across Cherry Creek from Auraria and named it "Denver City" in honor of James W. Denver, the current governor of the Kansas Territory. Larimer did not intend to mine gold himself; he wanted to promote the new town and sell real estate to eager miners.
Larimer's plan to promote his new town worked almost immediately, and by the following spring the western Kansas Territory along the South Platte was swarming with miners digging in river bottoms in what became known as the Colorado Gold Rush. Early arrivals moved upstream into the mountains quickly, seeking the lode source of the placer gold, and founded mining camps at Black Hawk and Central City. A rival group of civic individuals, including William A.H. Loveland, established the town of Golden at the base of the mountains west of Denver, with the intention of supplying the increasing tide of miners with necessary goods.

Early settlements, trade, and gold mining
The movement to create a territory within the present boundaries of Colorado followed nearly immediately. Citizens of Denver and Golden pushed for territorial status of the newly settled region within a year of the founding of the towns. The movement was promoted by William Byers, publisher of the Rocky Mountain News, and by Larimer, who aspired to be the first territorial governor. In 1859, an informal movement to establish the Territory of Jefferson was launched, with entreaties sent to the United States Congress for its official organization.
Congress did not wait long in granting the request of the citizens, partly encouraged by the promise of vast mineral wealth in the region. The territory was officially organized by Act of Congress on February 28, 1861, out of lands previously part of the Kansas, Nebraska, Utah, and New Mexico territories. Technically the territory was open to slavery under the Dred Scott Decision of 1857, but the question was rendered moot by the impending American Civil War and the majority pro-Union sentiment in the territory. The name "Colorado" was chosen for the territory. It had been previously suggested in 1850 by Senator Henry S. Foote as a name for a state to have been created out of present-day California south of 36° 30' To the dismay of Denverites, the town of Golden became the territorial capital, a situation that was rectified to the advantage of Denver as it grew at the expense of Golden.

The movement for statehood

Pike's Peak Country
Jefferson Territory
Historic regions of the United States