Recently I was helping a client try to prove that his immigrant ancestor had not been naturalized and this resource was very helpful:

The USCIS (US Customs and Immigration Service) maintains historical records documenting the arrival and naturalization of millions of immigrants who arrived in the United States since the late 1800s or/and naturalized between 1906 and 1956.

The USCIS Genealogy Program is a fee-for-service program that provides researchers with timely access to historical immigration and naturalization records of deceased immigrants.

Index Search: Using biographical information provided by the researcher, USCIS searches its historical immigration and naturalization record indices for citations related to a specific immigrant. Search results (record citations) are returned to the researcher, along with instructions on how to request the file(s) from USCIS or the National Archives. Fee: $20

Record Copy Request: Researchers with valid record citations (USCIS file numbers), gained through a USCIS Genealogy Program index search or through independent research, may request copies of historical immigration and naturalization records. Fee: $20/$35 depending on the record type.

The records and their span dates available through the USCIS Genealogy Program are:

  • Naturalization Certificate Files (C-files) from September 27, 1906 to April 1, 1956;
  • Alien Registration Forms from August 1, 1940 to March 31, 1944;
  • Visa files from July 1, 1924 to March 31, 1944;
  • Registry Files from March 2, 1929 to March 31, 1944;
  • Alien Files (A-files) numbered below 8 million (A8000000) and documents therein dated prior to May 1, 1951.

Individuals may submit genealogy records requests by using the forms, G-1041 – Genealogy Index Search Request and G-1041A – Genealogy Records Request. Both forms are available on the USCIS Genealogy Program page at: http://www.uscis.gov/genealogy.

The fees are:

Genealogy Index Search – $20

Copy of a File on Microfilm – $20

Copy of a Textual File Copy – $35