The original inhabitants of the area that is now Colorado included the Ute, the Apache, as well as Cheyenne, Arapaho, and Sioux.

The 1833 Bent's Fort fostered a trading system between Native Americans and fur trappers. The first permanent non-native settlement was the town of San Luis, founded in 1851. A year later, Fort Massachusetts (subsequently Fort Garland), was built on the Ute Creek to protect travelers on the Santa Fe Trail. At that time most migrants were not settling in Colorado but rather moving through to California and Oregon.

The territory of Colorado was formed in 1861 with seventeen counties. It joined the Union August 1, 1876 as the thirty-eighth state.

Migrants to Colorado came from states that ranged from New York and Pennsylvania on the east to Kansas and Nebraska on the west. In 1860 the greatest number came from Ohio, followed by Illinois, New York, Missouri, and Indiana. The population exploded after the Civil War, bringing native-born Americans from Missouri, Kansas, Nebraska, and Iowa. The population also included a large number of foreign-born immigrants including Czechs, Slovaks, Irish, Germans, Russians, Canadians, Swedish, Scots, Italians, and Chinese. By 1880, one-fifth of the population of Colorado was foreign-born and the state had three official languages: English, Spanish, and German. In the 1890s more Germans arrived, an ethnic group that continues to dominate in eastern Colorado today.

This guide offers a selection of resources and strategies for Colorado local history and genealogy research. These include the print and digital collections of the Library of Congress, as well as external repositories and web sites key to finding forebears in the Centennial State.