Source Information U.S., Index to Alien Case Files,1944-2003 [database on-line]. Lehi, UT, USA: Operations, Inc., 2022.
Original data: Index to Alien Case Files at the National Archives at Kansas City, compiled ca. 1975–2012, documenting the period 1944– 2003. Data file. Records of the U.S. Citizenship and Immigration Service (USCIS)., Record Group 566. National Archives and Records Administration, Washington, D.C.

About U.S., Index to Alien Case Files,1944-2003

If your ancestor was an alien in the U.S. in or after 1940, one record you will want to look for is an alien case file (A-File). This database contains an index to A-Files created between 1944 and 2003 for immigrants who were born before 1909.

What’s in an A-File?

The content of A-Files will vary depending on the immigrant and his or her interactions with the INS. Here are a few records that you might find in an A-File:

  • visas
  • AR-2 form (alien registration)
  • petitions and affidavits
  • correspondence
  • photographs
  • identification documents

What Is an A-File?

One provision of the Alien Registration Act of 1940 (also known as the Smith Act) required aliens aged 14 and older living in or entering the United States to register and be fingerprinted. The Immigration and Naturalization Service (INS)—now the U.S. Citizenship and Immigration Service (USCIS)—drew up the Alien Registration form AR-2 to register aliens beginning in 1940. AR-2 forms asked for a number of valuable family history details:

  • name (and any aliases used)
  • residence
  • date and place of birth
  • country of citizenship
  • marital status
  • physical description
  • most recent arrival in the U.S. (port, date, and ship)
  • occupation
  • employer
  • U.S. naturalization status
  • whether the alien had immediate family in the U.S.
  • statement of alien’s military service

Each form also included an A-number, which was later used to establish Alien Registration Files, or A-Files. A-Files typically (but not always) include the alien’s AR-2 form, as well as all other documentation created through the immigration and citizenship processes prior to naturalization. If the immigrant naturalized prior to 1 April 1956, the contents of the A-File were moved to a new Certificate File, or C-File, eliminating the A-File. This practice ceased on 1 April 1956, and from then on, all of the records remained in the A-File, regardless of whether the immigrant eventually naturalized. So, if an immigrant did not naturalize prior to the 1 April 1956 date, or never naturalized, their records would still be found in his or her A-File.

In 2010, the USCIS began transferring records of immigrants who were born more than 100 years ago to the National Archives for retention. This database contains an index to A-Files created between 1944 and 2003, for immigrants who were born before 1909. The files themselves are now held at the National Archives Regional Archive at Kansas City, Missouri, though immigrants mentioned in them come from around the United States. Note: Files from the Reno, Nevada; San Francisco, California; Honolulu, Hawaii; and Guam districts of the Immigration and Naturalization Service were transferred to the National Archives Regional Archive in San Bruno, California, and are currently not included in this index.

Ordering Your Ancestor’s A-File
The original case files are located at the National Archives at Kansas City. Please make sure to include the Alien Registration Number and the individual's complete name when requesting a copy of a file. The National Archives will accept requests by e-mail, postal mail, or fax.

E-mail: [email protected]

Postal mail:
National Archives at Kansas City
Attn: A-Files Request
400 W. Pershing Rd.
Kansas City, MO 64108

Fax: (816) 268–8038

For more information on ordering records from the National Archives, visit the National Archives website. To learn more about the records and the process for ordering files that are held at the USCIS, see their Genealogy section.