Colorado SSN lookup

The first three digits of an old-style SSN could point to Colorado when they fell inside one of these published ranges.

These rows show the issued area and group combinations linked to Colorado. Open any pattern as a full lookup by swapping in the last four digits.

This page covers issued SSN patterns for Colorado from 524-07-#### to 524-64-####. If you are scanning older prefixes or comparing issue-year ranges, this gives you a faster way to narrow the search.

Each row represents a valid issued area and group combination under the old system. Open any row to run a full number check and see the likely location and year range.

If an SSN starts with one of the prefixes above, Colorado is a likely issue location under the old system.

To check the number further, run the full nine digits through the checker. The result page can then tell you whether the group fits the published record and what year range the number most likely falls into.

Example old-style prefix for this page: 521-01-0001