Naturalization Records

About the Records

The Colorado State Archives has naturalization records for many of the counties in Colorado. People, immigrating to Colorado between 1861 and 1906 could file for naturalized status in the county, district, or sometimes even the criminal courts. While this function became primarily a federal responsibility thereafter, many state district courts continued to record naturalizations after 1906.

Before 1906, the primary record series include which were usually filed in a Naturalization Record volume. These earlier naturalization records include less information than later documents. Typically, there is only the applicant's name, the name of the clerk of the court, the name and title of the head of state the applicant renounced allegiance to, and the date of the document.

Also note, between 1855-1922 alien women were granted automatic citizenship if they were the wife of a United States or naturalized citizen. Therefore, we may not have any specific documentation showing the naturalization of a woman during this time period.

How to Find Information

Naturalization Records held by the Colorado State Archives

The following naturalization records are searchable using our Archives Search database:

  • 1889-1903     Bent County naturalization index
  • 1865-1867     Clear Creek County naturalization index
  • 1878-1906     Clear Creek County naturalization index (not a definitive index for this time span)
  • 1860-1958     Larimer County naturalization index
  • 1872-1915     Las Animas County naturalization index
  • 1903-1906     Park County naturalization index

For additional help in your research, try the National Archives and Records Administration naturalization page