The Social Security Death Index (SSDI), or Death Master File (DMF) is an index of the deaths of US persons that have been notified to the US Social Security. It's available online at various places including FamilySearch. It shows the social security number (SSN), age, and (for more recent data) the last place of residence of a person.

I understand that the primary use of the SSN on these records is to apply for a copy of the person's social security card application form SS-5, which often reveals information about them (such as parents names).

In addition, it's possible to find the place of issue of an SSN (issued before 2011). This is listed as "state" on the FamilySearch results. It can give clues as to where a person was (with many exceptions) when they first needed a Social Security card, such as when they first started working.

However, are there any other uses for the SSN? Are there any US public records, applicable to a deceased person, that use or include the SSN? For example, is there such a thing as a historical credit file that might show residential addresses over time? Are there historical voter records that include it?

Are there open historical tax records? Is the SSN used in public military records, or in university alumni records? (Whether the number should have been used for such purposes is outside the scope of this question).

In other words, given the SSN of somebody who died possibly decades ago, are there any other records it could provide a key to?

  • I've added a section to my answer with links to Ancestry's SS Application and Claims Index, and the new free NUMIDENT database at NARA (part of their AAD website).
    – Jan Murphy
    Nov 18, 2016 at 23:10
  • 1
    The LDS (familysearch.org) no longer include the SSN in search results.
    – WGroleau
    Jan 7, 2019 at 22:53

2 Answers 2


The only U.S. tax records that have been made public are pre-Internal Revenue Service (and therefore pre-SSN). I expect there would be a major furor should anyone propose making even 100-year-old IRS records public, but you never know. Same issue for credit records (and, since credit agencies are non-governmental, even less likely).

Social Security numbers are considered private information until the SSN-holder dies, so it won't appear in things like voter records. There was a brief period when it was included in some public records, but that trend has quickly died (and reversed). The original purpose of the SSDI was for third parties with a legitimate interest (e.g., other federal agencies, state governments, employers) to determine whether the SSN was being used fraudulently.

There are at least two kinds of records where SSNs do (sometimes, but not always) show up - death certificates and burial records. In the State of Pennsylvania, death certificates included a field for SSN starting in mid-1941 (although for quite awhile, the space was often left blank, or entered as "none"). I presume that other states are similar.

Pennsylvania veterans' burial cards sometimes also include the deceased's SSN along with their military service serial number. I've also seen the SSN listed in the burial records on some cemetery websites (I don't recall whether any of them will let you search using SSN).

It's mostly useful as evidence that the death certificate or burial record matches the SSDI, in case one or the other is missing something like the DOB or middle name. So far as using it as a key, not so much.

  • 1
    That's a good point about the SSN sometimes appearing on death certificates, such as genealogy.az.gov/azdeath/0250/2501749.pdf -- however that state (Arizona) doesn't appear to index the numbers nor (as a result) offer any way to search by them. Probably the same for most/all states. But, as you say, the SSN is a good way to cross-check it's the same person once the record has been found some other way.
    – Rob Hoare
    Jan 15, 2014 at 3:34

The SSA retrospective The Story of the Social Security Number traces the changes in Social Security card evidence requirements from 1936–2008, and has a table of legislated and regulatory requirements for using Social Security numbers (SSNs) from 1943–2008.

These tables provide clues as to what other records may have been created about an individual that might contain an SSN. If you have any of those records, matching the SSN will give you some confidence that the records belong to the same individual. However, there are some things to consider:

  1. Cases exist where duplicate SSNs were assigned (see the linked article for details).
  2. Many records from organizations which may have asked for SSNs hold those records in confidence, and privacy concerns may bar public access.
  3. Even when records are accessible, they may not be retrievable by the SSN.

The article is also available for download as a PDF.

I don't know if any of the records referred to in this article are open to the public, but it might be a starting point for further research.

Is the SSN used in public military records?

The SSN appears in Ancestry's database U.S., Department of Veterans Affairs BIRLS Death File, 1850-2010 / fold3's Veterans Affairs BIRLS Death File. The NIH's US Library of Medicine has a fact sheet that describes how the BIRLS Death file is updated.

In my own research, I match the SSN from the following databases and records whenever possible:

Note that not all Social Security Numbers were applied for with an SS-5 form. See "A Taxing Form" posted on 8 Dec 2014 by Judy Russell, on her blog The Legal Genealogist.

The blog post Anatomy of a Social Security Number has information about what geographical clues might be found in the SSN itself (and the periods for which this is the case). It also lists several of the beneficiary codes (letter codes) that may appear on documents when SSNs are used as claim numbers for Social Security or Medicare Benefits.

The Social Security number followed by one of these codes is often referred to as a claim number. The SSA assigns these codes once someone applies for benefits. These letter codes may appear on correspondence from Social Security or on a Medicare card. They will never appear on a Social Security card.

Two more recent blog posts (July 2015) from The Legal Genealogist:

In November of 2016, the US National Archives added to its Access to Archival Databases (AAD) website a related group of records from the Social Security Administration, the NUMIDENT files. A PDF on the content and scope of these digital records can be downloaded here: Freqently Asked Questions: Series: Numerical Identification (NUMIDENT) Files, 1936 – 2007 Record Group 47. Section II.4 of this document addresses the differences between the data in the SSDI and this database.

If you have the SSN of a deceased person, you can now search AAD for free to find out other information about how that person communicated with the Social Security Administration. You don't need a subscription, as you would to search Ancestry's U.S., Social Security Applications and Claims Index, 1936-2007. See Ancestry's About U.S., Social Security Applications and Claims Index, 1936-2007 underneath the search box on the previously-linked page for their explanation of what information might be found in this database.

One example from my research: my husband's grandmother's record on NARA's AAD extracts from the NUMIDENT has a value in a field marked "Other Number". A search of my files showed that the number is her husband's SSN. This associates the two numbers, showing me that I'm likely to have the right couple (and not two individuals who happen to have similar names). It also means I have another way to find her entries in the database -- which is important, since her surname is misspelled in both the SSDI and NUMIDENT files.

UPDATE: Having spouses' records linked via the "Other Number" is not very common. NARA's FAQ says, in part:

For 71% of the records, the Other Number field contains the same value as the Social Security Number field. And 13% of the records are blank or have a null value for this field.

(One drawback of the NUMIDENT extracts at AAD is that NARA redacted the content of the death Certificate number file. If they had included that data, I could have matched it against the state's death index, which does include that information.)

  • For people outside the USA, this website might be of interest -- International Social Security Association: issa.int
    – Jan Murphy
    Jan 11, 2014 at 23:39
  • The "exhibit 2" list in that document does indicate when some types of usage of the SSN started. Federal employee numbers in 1961, Veterans records from 1966, an military identification number from 1969 seem the most potentially useful. I'm surprised how recent most of the other uses were. Property records (real estate) are a source I didn't think of. But for all these I'm not aware of anything that is searchable by SSN, yet.
    – Rob Hoare
    Jan 15, 2014 at 3:29
  • As cleaverkin says, the main value is seeing whether the SSN matches the SSN found in other records. But until I read that article, I had no idea how many duplicate SSNs were issued. That would make searching by SSN ... interesting.
    – Jan Murphy
    Jan 17, 2014 at 7:51

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