Social Security numbers (SSNs) are nine-digit identifiers formatted as XXX-XX- XXXX and were originally assigned in a specific pattern that conveyed geographic and administrative information. Until June 25, 2011, the first three digits (the area number) indicated the state or region where the SSN was issued, based on the applicant's address or application location. The middle two digits (group number) were assigned in a specific non-sequential pattern to help the Social Security Administration (SSA) manage issuance within each area. The final four digits (serial number) were assigned sequentially. However, since June 25, 2011, SSNs are assigned randomly to eliminate geographic significance and protect against identity theft. This randomization expanded the pool of SSNs, helping prevent exhaustion of available numbers and making it harder for criminals to guess valid numbers based on location or known patterns. The randomization preserves the nine-digit format, but now all parts of the SSN are assigned by a computer-generated random process, except for the exclusion of certain invalid number combinations such as 000, 666, and numbers in the 900-999 range for the first three digits. In summary, SSNs were originally assigned with geographic and administrative structure, but today they are assigned randomly by the SSA to enhance security and maintain number availability over time.
