Finding and Using Alien Records
Researching immigrant ancestors can be challenging. Family historians often search for naturalization records to learn more about immigrants, but what if they were never naturalized? Alien records, including Alien Registration Forms (AR-2s) and Alien Files (A-Files), can provide a wealth of information, and are sometimes the only records that identify the origins of twentieth-century immigrants.
Alien Registration Forms (AR-2s)
The Alien Registration Act of 1940 called for all non-citizens living in or entering the United States to register with the government. Between August 1940 and March 31, 1944, more than five million people (including children over the age of fourteen) completed an Alien Registration Form (AR-2). These forms, required by the Immigration and Naturalization Service (INS), provide the following information:
- Name (and maiden names, former married names, aliases, professional names, and nicknames)
- Address
- Date and place of birth
- Citizenship
- Marital status
- Gender, height, weight, hair color, and eye color
- Date of first arrival in the United States
- Name upon last arrival in the United States
- Date of last arrival in the United States, and the port, ship, and class of admission
- Number of years living in the United States
- Occupation and employer
- Organization memberships and activities
- Military service (abroad)
- Citizenship application status (when and where a declaration was filed)
- Number of relatives in the United States (parents, spouse, or children)
- Criminal offenses
AR-2s also include the date and place of registration, and the immigrant’s signature and fingerprint. Supplemental pages are sometimes appended to the AR-2. The information included on the AR-2, such as variant surname spellings, dates of arrival, and birth locations, can often lead to additional records that may have otherwise been difficult to locate.
When the INS received an AR-2, they stamped it with an A-number and provided the registrant with an alien registration receipt card. Today, AR-2s are arranged by (and must be requested by) A-number. A-numbers can sometimes be found in home sources—such as alien registration receipt cards or naturalization records—but can more reliably be found by requesting a search of the United States Citizenship and Immigration Services (USCIS) indexes.
The USCIS indexes are not available to the public due to privacy restrictions, but a search can be requested through the USCIS website for a $20 fee. The search will determine whether USCIS records, including AR-2s, Alien Files, Citizenship Files, Visa Files, and Registry Files, exist for a specific individual. If an AR-2 exists, a copy of the record can be ordered through USCIS.
Alien Files (A-Files)
Beginning on April 1, 1944, the INS began creating Alien Files (A-Files) in an effort to consolidate the various records held by the agency for each individual. Immigrants who arrived in the United States after this date will have A-Files. Individuals who filled out an AR-2 will only have an A-File if their case was “reopened” after April 1, 1944—for example, if they filed a change of address form, requested a replacement identification card, were the subject of an investigation, or had some other interaction with the INS. (Immigrants who naturalized will not have an A-File. Upon naturalization, all of his or her INS records, including alien records, would have been transferred to a Certificate File, also known as a C-File.)
A-Files can include AR-2s, as well as other documents such as visas, investigative reports, change of address forms, and various other records kept by INS. In some instances, A-Files include records of birth, baptism, and marriage that can lead to additional sources in the immigrant’s country of origin. Many records in A-Files include photographs. A-Files can consist of a few pages or hundreds of pages of records.

Photograph and signature of Giuseppe Angello of Irvington, New Jersey, from Form AR-AE-22 (Application for Certificate of Identification), 1942. Courtesy of the National Archives and Records Administration.
A-Files for individuals who would be over 100 years old are transferred from USCIS to the National Archives in five-year blocks. At the time of this writing, the National Archives has A-Files for individuals born in 1910 or earlier; an additional five years of records will be transferred in the future. These A-Files are held primarily at the National Archives at Kansas City, but select A-Files from the San Francisco, Honolulu, Reno, and Guam INS districts are housed at the National Archives at San Francisco.
The National Archives Online Public Access (OPA) catalog can be used to search for A-Files for individuals born in 1910 or earlier. (The catalog presently includes the names of all individuals whose A-Files are held in either San Francisco or Kansas City.) The best option is to use OPA to search by name specifically within Record Group 566 (Records of USCIS). A catalog entry will include the individual’s date of birth, date and port of entry, nationality, and alien registration number, as well as the file’s identification number and location (Kansas City or San Francisco), and contact information for the facility that holds the record.
A-Files for individuals born after 1910 are still with USCIS. The same index search outlined above will determine whether an A-File for exists for a specific person. A-Files for these individuals, who either (1) registered as aliens after 1940 or (2) arrived between April 1, 1944 and May 1, 1951, will have A-numbers below 8,000,000. These records can be ordered through USCIS. More recent records (with A-numbers 8,000,000 and higher) must be ordered through a FOIA request, and some information may be restricted due to privacy concerns.
Who Was Considered an Alien?
Knowing whether alien records may exist for a specific person requires an understanding of US citizenship laws. Foreign-born individuals who had not naturalized are obvious candidates; however, A-Files also exist for women whose alien statuses may be surprising.
A woman’s citizenship was often impacted by marriage. Between March 2, 1907 and September 22, 1922, a woman lost her US citizenship if she married a man who was not a citizen. If she hadn’t become a citizen through her husband’s naturalization, naturalized on her own, or taken an oath of allegiance to gain back her citizenship, she would have been required to register as an alien in 1940 by filling out an AR-2 form.
After the Cable Act was passed in 1922, a woman’s citizenship was no longer tied to her husband. Women who were US citizens no longer lost their citizenship through marriage. On a similar note, women no longer became citizens automatically when their husbands naturalized. As a result, many foreign and American-born women were aliens, even when their husbands were citizens. Alien records exist for these women.
Alien records may also be found for:
- foreign-born individuals who entered the United States but did not stay;
- citizens who were unsure of their citizenship status, perhaps due to confusion about whether their father had naturalized, or how their marriage impacted their citizenship; and
- individuals who had filed a declaration of intention by 1940, but hadn’t yet been naturalized.
Do you have ancestors who were aliens after the Alien Registration Act of 1940 was passed? If so, consider learning more about them by looking into the alien records available through USCIS and the National Archives.
Your article on “Finding and Using Alien Records” was very informative. I do have one question, if you have time. I have the Immigration/Passenger Lists for my ancestors who came into the U.S. in 1907 (father-in-law), and 1911 (mother-in-law to-be). Mother-in-law was 10 yrs. at the time, and came in with her parents. I always thought that if the parents were naturalized, then the children would automatically be included. If that isn’t true, and my mother-in-law was already naturalized, would she have lost her citizenship when she married circa 1920?
Thank you.
Loretta Kalmar
Hi Loretta,
Thank you for posting. Until 1940, children under the age of 21 were automatically naturalized when their father was naturalized. If your mother-in-law’s father naturalized before she was 21 years old, your mother-in-law would have become a U.S. citizen. If your mother-in-law married your father-in-law before September 22, 1922 and he was not a U.S. citizen, then she would have lost her U.S. citizenship (and gained whichever citizenship your father-in-law held). However, your mother-in-law could have become a U.S. citizen again if (1) her husband naturalized shortly after they married (but before 1922), (2) she naturalized on her own, or (3) she took an oath of allegiance. (Beginning in 1940, women who had lost their U.S. citizenship by marriage between 1907 and 1922 were allowed take an oath of allegiance to gain it back.) You may want to check federal and local naturalization indexes to see if any of these events occurred. You could also check the 1940 census to see whether your mother-in-law is identified as a naturalized citizen or as an alien (in column 16). If it appears that your mother-in-law had not gained her citizenship back by 1940, she should have completed an AR-2 form (and she may even have an A-File, depending on the circumstances). Best of luck with your research.
Great article, Melissa. A-files are particularly important for Chinese and Japanese research. Thank you.
Linda Okazaki
Good article! I’ve been wanting to research Alien registrations, so thanks. One question though – I had read/heard that there was a requirement for aliens to register during the WW1 years – any truth to that?
Hi Mark,
Yes, alien registration was also required between November of 1917 and April of 1918. However, most of these records no longer exist. Those that do survive are held at various locations (mostly on the local level), such as public libraries, state archives, and historical societies. Records for some states, such as Kansas, are available online: http://search.ancestry.com/search/db.aspx?dbid=2137. The records can provide valuable information, so you may want to check and see if they exist for the area where your ancestors lived. Good luck with your research.
Thanks so much for all this fabulous information! I’m going to enjoy digging even more!