Colorado History and Research Overview

By Family Tree Editors Premium


Zebulon Pike arrived in 1806 to explore the area that would become Colorado. Half a century later, the promise of gold brought early settlers to the mountains of Colorado.

In 1803, the Louisiana Purchase brought the part of Colorado north and east of the Arkansas River under US control. Government expeditions soon began mapping the area. By the 1820s, fur trappers and traders had begun moving in.

In the 1840s, Mexican land grants in Southwestern Colorado brought Hispanic settlers. In 1848, the United States acquired the rest of Colorado from Mexico and agreed to honor claims to earlier Spanish and Mexican land grants. Settlers from Spanish New Mexico settled in the San Luis Valley beginning in 1851. In 1852, Fort Massachusetts was built. Fort Garland was the second military outpost in Colorado.

Denver and many other mining towns were formed as the 1858 Pikes Peak Gold Rush brought a flood of settlers, primarily from the Midwest and Northeast, but there were some from almost every part of the United States, as well as many foreign immigrants.

Colorado Territory was organized in 1861. By the time of the 1870 census, the transcontinental railroad linked Denver with Cheyenne, Wyo., and Kansas City, Mo., providing direct connections to the East and West coasts. By then, the Plains Indian inhabitants, primarily Arapaho, Cheyenne, Kiowa and Comanche, had been forced to move to Indian Territory in Oklahoma, leaving only the Ute. In 1876, Colorado became the 38th state. The Ute were relocated to Utah reservations, and in 1881, western Colorado opened for settlement.

The gold rush era began to wane after the last major gold strike at Cripple Creek in 1890. By 1910, the midwestern states were the primary feeders for migration to Colorado, but many immigrants came from Germany, Russia, Italy, Austria, Sweden and England. Mining, ranching and later, oil and industry, continued to be prominent in the development of Colorado throughout the 20th century.

(click to enlarge)
Colorado state map with county outlines



  • Federal census: 1880, 1885, 1900, 1910, 1920, 1930
  • Federal mortality schedules: 1860 (with Kansas), 1870, 1880
  • 1860 territorial census and mortality schedules: Nebraska 1860 (schedules designated “unorganized territory” which became northeastern Colorado), Arapahoe County, Kansas Territory 1860 (central eastern Colorado), Toas and Mora Counties of New Mexico Territory 1860 (southeastern Colorado)
  • 1870 Colorado territory census and mortality schedules


  • Colorado Area Key: A Comprehensive Study of Genealogical Records Sources of Colorado, Including Maps and Brief General History compiled by Florence Runyan Clint (Eden Press, 1968)
  • Colorado Bibliography edited by Bohdan S. Wynar and Roberta J. Depp, assistant editor (Libraries Unlimited for the National Society of Colonial Dames of America in the State of Colorado, 1980)
  • Colorado Families, a Territorial Heritage (Colorado Genealogical Society, 1981)
  • Colorado Postal History: The Post Offices by William H. Bauer, James L. Ozment, and John H. Willard (J-B Publishing Co., 1971)
  • Colorado Research Outline by the Church of Jesus Christ of Latter-day Saints (online at
  • Genealogical Index to the Records of the Society of Colorado Pioneers by the Society of Colorado Pioneers, the Colorado Genealogical Society, and Bette D. Peters (Colorado Genealogical Society, 1990)
  • Guide to Colorado Newspapers, 1859-1963 compiled by Donald E. Oehlerts (Bibliographical Center for Research, Rocky Mountain Region, 1964)
  • Pioneers of the Territory of Southern Colorado by the Territorial Daughters of Colorado, Southern Colorado Auxiliary (1980)
  • Subject Index to the Colorado Genealogist by Kay R. Merrill (Colorado Genealogical Society, 1982)

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