Colorado Naturalization Records

What is Naturalizaton?

Naturalization is the process by which a foreign-born person becomes a citizen of the United States. 

  • Before 1906, any "court of record" (municipal, county, state or federal court) could grant U.S. citizenship 
  • After the Basic Naturalization Act of 1906 was enacted, naturalization forms were standardized and state and local courts were encouraged to pass their naturalization jurisdiction to federal courts

What can I find in Naturalization Records?

Records generated through the naturalization process can be a rich source of information for researchers, offering insight into an immigrant's place of origin, original name, former residence and date of arrival into the U.S. 

From 1906 to 1952, naturalization was a two-step process which yielded two types of records especially meaningful to genealogical researchers:

  1. Declaration of Intention (known as "First Papers")
    • Pre-1906 records contain little biographical information
    • Post-1906 records can contain name, address, occupation, birthplace, nationality, country of origination, birth date or age, physical description, marital status, number of children, and the name of the applicant's spouse 
  2. Petition for Naturalization (known as "Second Papers" or "Final Papers")
  • The petition could occur two years after a Declaration of Intent was filed, assuming that residency requirements had been met (generally five years). Information that may appear in this petition includes: petitioner's name, current residence, occupation, birth date and place, personal description, date of arrival in the U.S, arrival and departure port locations, date when U.S. residence began, length of residence in the state, name changes, marital status (and possibly spouse's name), dates and places of birth and residence of the petitioner's children

Where can I find Colorado Naturalization Records?

Research Tools

Naturalization Records, 1877-1952 – U.S. District Courts, Denver & Pueblo (INDEX)

Naturalizations created in the district courts of Denver and Pueblo, Colorado, including:

  • Federal District Courts. Declaration of Intentions, 1877 - 1952
  • Denver, Colorado. Naturalizations, 1906 - 1950
  • Pueblo, Colorado. Declarations of Intentions, 1906 - 1949
  • Pueblo, Colorado. Naturalizations, 1912 - 1949
  • Pueblo, Colorado Soldier's Petition for Naturalization, 1918 - 1928

This index references microfilm reels available in the Special Collections and Archives Department: Naturalization records created by the United States District courts in Colorado, 1877-1952 [microform].

Naturalization Records, 1867-1964 – Colorado County Courts (INDEX)

Colorado state naturalization records from 1867-1964, including names of individuals, spouses, counties, and citations to official records. Primary source for the data, originally created at the county level, comes from microfilmed records at the Colorado State Archives. Some original print records were returned to the county. All location information in the tables refer to the Colorado State Archives.

Data is not included for Boulder, Denver, Fremont, Las Animas, and Pueblo counties. References to sources for that data are provided in the appendix at the end of the document.