How Social Security Numbers Work

The Three Parts of the Social Security Number

Each SSN is nine-digits, broken into three sections:

Area Number

For the most part, the government has assigned numbers starting in New England and moving to the south and west from there. People on the eastern seaboard typically have the lowest numbers, while those in California have the highest.

The Area Number refers to a geographical region of the United States, usually a state or territory. Prior to 1972, the government issued social security cards from local offices around the country, with the Area Number specifying the state where the card and number were issued. This wasn't necessarily the state where the individual resided, since one can apply for a card in any office. After 1972, when the government began assigning SSNs and cards centrally from an office in Maryland, this number has been based on the zip code from the mailing address provided by the applicant. Of course, a person's mailing address isn't necessarily the same as their place of residence. So, the Area Number does not always represent the applicant's state of residence.

Group Number

Within each area, the group number (middle two (2) digits) range from 01 to 99 but are not assigned in consecutive order. For administrative reasons, group numbers issued first consist of the ODD numbers from 01 through 09 and then EVEN numbers from 10 through 98, within each area number allocated to a State. After all numbers in group 98 of a particular area have been issued, the EVEN Groups 02 through 08 are used, followed by ODD Groups 11 through 99.

Serial Number

Within each group, the serial numbers (last four (4) digits) run consecutively from 0001 through 9999.

Group Numbers

Apparently due to the fact that the middle digits of the SSN are referred to as the "group number," some people have misconstrued this to mean that the "group number" refers to racial groupings. So a myth goes around from time-to-time that encoded in a person's SSN is a key to their race. This simply is not true.

As should be clear from the explanation of the SSN numbering scheme, the "group number" refers only to the numerical groups 01-99. For filing purposes, the "area numbers" are broken down into these numerical subgroups. So, for example, for area numbers starting with 527 there would be 99 subgroups, one for every number starting with 527-01, and one for every number starting with 527-02, and so on. This was done back in 1936 because in that era there were no computers and all the records were stored in filing cabinets. The early program administrators needed some way to organize the filing cabinets into sub-groups, to make them more manageable, and this is the scheme they came up with.

So the "group number" has nothing whatever to do with race.