https://colorado.phonenumbers.org/
A phone number lookup or reverse phone search refers to the act of retrieving the registrant's details for a number that called you.

https://lookify.io/search/state/colorado
Another approach to perform a reverse phone lookup in Colorado for free is through government websites and public records. The Colorado Judicial Branch website ...

https://www.whitepages.com/white-pages/co
Lookup People, Phone Numbers, Addresses & More in Colorado (CO). Whitepages is the largest and most trusted online phone book and directory.