The United States Social Security Number area code used to startwith a number less than 740 bt this is no longer the case: https://www.ssa.gov/history/ssn/geocard.html There are now routinely SSNs with area code larger than 740. https://github.com/SpiderLabs/ModSecurity/blob/60f802e4801c8a4fee8e2caac90462e53651971f/src/operators/verify_ssn.cc#L103