Naturalization Index (1800-1991)

The first United States naturalization act was passed in 1790 and stated that individuals could be naturalized in any federal, state, or local court. Immigrants typically applied for naturalization at the court nearest to their home so finding their initial place of residence is important. Naturalization is the formal process of granting citizenship to foreign-born residents. Naturalization records may consist of three separate documents filed during an immigrant’s naturalization process: Declaration of Intention, Petition, and Certificate. These documents could have been filed in separate locations.       

After living in the U.S. for a period of time (generally three years) an immigrant could file their first papers known as their ‘declaration of intention.' This declaration renounced their allegiance to their former country. After waiting an additional period of time (generally two years), an immigrant could ‘petition’ for their final naturalization papers. Certificates of naturalization were the final papers issued by the courts. Prior to 1906 naturalization was handled by individual states and local county courthouses with records providing minimal information such as an immigrant’s name and native country.

Beginning in 1906 the naturalization process was standardized with the creation of the federal Bureau of Immigration. Naturalization records filed beginning in 1906 are more detailed and generally contain genealogical information such as the spouse’s name, certificate of arrival, age, occupation, date and place of birth, children’s names, and current residence. Federal naturalization laws further required Declarations of Intention for immigrants that arrived after 1906 to list the name of the vessel they arrived on. Naturalization records may document name changes after an immigrant arrived. Immigrants may have had several names or aliases in their homeland. Many immigrants boarded the ship with a ticket that bore a name different than the one they used in America. Naturalization records are valuable because they provide an ancestor’s original signature which is an important link for researching your roots in another country.

Search Tip: The ‘Naturalization Files’ record series consist of both Declarations of Intentions and Petitions which were microfilmed together. If multiple references for the same individual are found view the Naturalization Files first since many naturalization Declaration of Intentions were also filed with the Naturalization Petitions.