Since 1973, social security numbers have been issued by our central office. The first three (3) digits of a person's social security number are determined by the ZIP Code of the mailing address shown on the application for a social security number. Prior to 1973, social security numbers were assigned by our field offices. The number merely established that his/her card was issued by one of our offices in that State. See also High Group List<span> of SSN's.</span>
