Immigration and nationality records changed over time. For this reason there is no one set of instructions to guide family history research. What records exist and how to find them depend entirely on when the immigrant arrived and if, when, or how they became a United States citizen.
If you are looking for immigration records from after May 1, 1951, or naturalization records from after April 1, 1956, you should visit the USCIS Freedom of Information Act and Privacy Act program page to find out how to request them.
Arrived before 1924
The official arrival record of immigrants who arrived before July 1, 1924, is a passenger list or manifest. Ship passenger lists for those who arrived 1820-1892 (Customs Lists) or 1892-1924 (Immigration Lists) as well as land border manifests for arrivals from Canada 1895-1924 and Mexico ca. 1905-1924 are available on microfilm at the National Archives or online subscription sites
Arrival before 1924 but arrival record cannot be found
Immigrants admitted for permanent residence during these years could not naturalize if no record of their arrival could be found. To qualify for naturalization after 1929 they could apply for Registry proceedings to create an immigration record. Registry Files document this activity between 1924 and 1929 and are available through the USCIS Genealogy Program. Many registry files were later moved to become part of an A-File or C-File after 1944.
Arrival 1924 to ca. 1944
Visa Files, the official arrival record of immigrants admitted for permanent residence between July 1, 1924, and March 31, 1944, are available through the USCIS Genealogy Program. Many Visa Files were later moved to become part of an A-File or C-File after 1944.
Arrival before August 1940 and not naturalized by August 1940
All noncitizens age 14 and older who resided in the U.S. in 1940 had to register under the 1940 Alien Registration Act. The Alien Registration Forms (AR-2) are available through the USCIS Genealogy Program.
Arrival between March 31, 1944 and May 1, 1951
All immigrants admitted for permanent residence during these years were originally documented in A-Files, a unified folder intended to hold all records related to one individual. If the immigrant naturalized before April 1, 1956, their A-File was converted to a C-File. A-Files numbered below 8 million (arrived before May 1, 1951) and C-Files 1906-1956 are available through the USCIS Genealogy Program.
Arrival after May 1, 1951
All immigrants admitted since May 1, 1951 should be entirely documented in an A-File, a unified folder intended to hold all records related to one individual. A-Files numbered 8 million and above (arrived May 1, 1951 and after) are available through the USCIS Freedom of Information Act and Privacy Act Program.
1790 to September 26, 1906
United States nationality law during this period delegated naturalization authority to any court of record, including Federal, State, and a variety of local courts. The court records vary over time and location. Though the majority of naturalization records of this era are not Federal records, the National Archives website provides basic guidance.
- Women and Children: The law before 1906 extended U.S. citizenship to the wife and minor children of a naturalized immigrant through derivation. Unfortunately, the law did not require the wife or children to be named in the record.
- Replacement Certificates: An immigrant naturalized before 1906 but who lost their certificate could, beginning 1929, apply for a replacement from the Federal Naturalization Service. The application and paperwork are available in “Old Law” C-Files from the USCIS Genealogy Program.
September 27, 1906 to March 31, 1956
Since 1906 all naturalization records were prepared in duplicate. The naturalization court retained the original and forwarded the duplicate to the U.S. Naturalization Service in Washington, D.C., for filing in USCIS C-Files. You can request a search of USCIS’ comprehensive index to all granted naturalizations since 1906 by submitting a USCIS Genealogy Index Search Request.
Women and Children: The 1906 law required the spouse and minor children of the naturalized citizen to be included on the petition and certificate documents. After 1929 women and children who derived U.S. citizenship through the naturalization of their husband or father (or women who acquired citizenship by marriage to a U.S. citizen) could apply for a Certificate of Citizenship in their own name. Each Certificate of Citizenship case is a C-File indexed by USCIS and available through the USCIS Genealogy Program.
- Repatriation: Naturalized or U.S.-born citizens who lost their nationality and later repatriated also have C-Files with USCIS. Typical cases include those who joined the Canadian Armed Forces in the early years of World War I, or women who married aliens between 1907 and 1922. Each repatriation case is a C-File indexed by USCIS and available through the USCIS Genealogy Program.
Since April 1, 1956
Courts continued to prepare duplicate naturalization records from 1956 to about 1992. USCIS filed the court documents in the immigrant’s A-File along with all other records of that individual.
Naturalization records from after April 1, 1956, are available from the USCIS Freedom of Information Act and Privacy Act Program.