The Alien Registration Act of 1940 required that all noncitizens entering and living within United States borders register their alien (noncitizen) status with the government. Individuals who were unsure of their citizenship status were also required to register even if it was later determined they were a U.S. citizen. The registration process included a questionnaire form and a requirement that fingerprints be taken at the time of registration (certain exclusions applied for diplomats, employees of foreign governments, and children under the age of 14). As Immigration and Naturalization Service (INS) received the completed Alien Registration (AR-2) forms, an Alien Registration Number (A-Number) was assigned (ex. A1234567) and an Alien Registration Receipt Card containing this number was mailed to each registrant as proof of registration.
The Alien Registration Program registered over 5.6 million noncitizens between August 1, 1940, and March 31, 1944, when the AR-2 records series closed. Alien Registration continued after April 1, 1944, but on different forms filed in a new series of individual records, Alien Files (A-Files).
The Alien Registration Division of the Immigration and Naturalization Service (INS) created the original Flexoline Index (Flex) in 1940 to index AR-2 forms.
INS microfilmed the completed AR-2 forms. Most of the original AR-2 forms were subsequently destroyed. However, some original AR-2 forms ended up in A-Files opened under the same A-Number when the subject immigrants had subsequent interactions with INS.
After the microfilm was converted to an electronic format, the AR-2 digital images were managed by INS, later United States Citizenship and Immigration Services (USCIS), as a component of the Microfilm Digitization Application System (MiDAS).
INS utilized multiple iterations of Alien Registration Forms from 1940 to 1944:
- Alien Registration Form (AR-2)
- Alien Registration Foreign Service Form (AR-102, completed at consular offices)
- Alien Registration Seaman Form (AR-102-S)
All iterations of the form are included in the Alien Registration (AR-2) Form series.