Prior to 1986 you didn't need a social security number until you had earned wages to report on a 1040. My mother for example didn't have a SSN until she was 62 at my father's death. And then it was his number with a suffix of 'D' (widow over 60 years of age).I didn't get mine until I was 14. My oldest son not until he was 16 and only then because it was 1986 and the law changed requiring SSN's generally for all those over the age of five.
There are still many religious groups in America today that don't have SSNs, legally. "Social Security was originally a universal tax, but when Medicare was passed in 1965, objecting religious groups in existence prior to 1951 were allowed to opt out of the system. Because of this, not every American is part of the Social Security program, and not everyone has a number."
The Area Number, the first three digits, is assigned by the geographical region. Prior to 1973, cards were issued in local Social Security offices around the country and the Area Number represented the office code in which the card was issued. This did not necessarily have to be in the area where the applicant lived, since a person could apply for their card in any Social Security office. Since 1973, when SSA began assigning SSNs and issuing cards centrally from Baltimore, the area number assigned has been based on the ZIP code in the mailing address provided on the application for the original Social Security card. The applicant's mailing address does not have to be the same as their place of residence. Thus, the Area Number does not necessarily represent the State of residence of the applicant, neither prior to 1973, nor since.