Historical area-number reference
Social Security Number Prefixes for Colorado
The historical area-number ranges listed for Colorado are 521-524, 650-653.
Plain-language answer
What Colorado prefixes mean
Before June 25, 2011, an older SSN beginning with an area number in the ranges below was associated with Colorado in the historical assignment record, usually through the mailing address on the original application.
For example, an old number beginning with 521 may fit this historical Colorado area-number record. This does not identify a person and does not show where the person lives now.
Listed ranges
Colorado area-number ranges
| Area-number range | Count of area numbers |
|---|---|
| 521–524 | 4 |
| 650–653 | 4 |
Know the limit
Why newer numbers are different
Randomization ended the geographic connection for new numbers. The first three digits of a newer SSN cannot reliably tell you a state or territory.
This page is an educational historical reference. It is not an identity lookup, background check or current-location search.
Quick answers
Colorado SSN prefix FAQs
What are the Social Security number prefixes for Colorado?
The historical area-number ranges listed for Colorado are 521-524, 650-653. These ranges apply only to older numbers issued before June 25, 2011.
Does a Colorado prefix show where someone lives?
No. A historical prefix was generally tied to the mailing address on the original application, not a current address, birthplace or identity.
Do these prefixes apply to newer SSNs?
No. Since June 25, 2011, new numbers have been assigned randomly and the first three digits no longer have geographic meaning.
Can this page identify a person?
No. A prefix is only a historical reference. It cannot confirm who owns a number or identify a person.