For SSNs issued before 1973, you need to know the location of the issuing office. For those issued after 1973, you need to know the mailing address on the appli

For SSNs issued before 1973, you need to know the location of the issuing office. For those issued after 1973, you need to know the mailing address on the application. Therefore, location of birth seems to be the most important piece of information, however you are led to it. This year, the process was randomized to reduce geographical significance and increase the amount of available numbers: http://www.ssa.gov/employer/stateweb.htm http://www.ssa.gov/employer/stateweb.htm