thenumchk

The distribution of SSN numbers in the US is well known including the special use for railroad and US territories with sequential numbers. I dissected much of that through historical publication of the death master database and made a lookup for it at https://numchk.com/ as a fun side project.

I did a deep dive into history of Social Security Numbers (SSN) in the united states from available information and wrote a poorly executed static site generated from the information with google adds. Does a few hundred USD a month. http://numchk.com/