307 covers Cheyenne, Casper, Gillette and more, on Mountain time. Paste a 307 number to see whether it is valid, mobile or landline, and whether it has been reported.
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By number of exchanges assigned to each rate centre — where most 307 numbers were issued.
The carrier each block of numbers was assigned to. A number that has been ported keeps its digits and changes network, so this is where a 307 number started, not necessarily where it is today.
Between Aug 25, 2026 and Oct 15, 2026, consumers filed 641 complaints with the FTC about 588 different 307 numbers; 62% were recorded messages. A caller ID can be spoofed, so a complaint against a number is evidence about calls showing that number, not proof about its owner. How 307 compares with other area codes →
Calling a list of 307 numbers? Check up to 20 at once on the free call list cleaner — line type, carrier and complaint history for each — or one number on the spam phone checker.
307 is in Wyoming, United States. Its busiest exchanges are in Cheyenne, Casper, Gillette, Cody.
Mountain (UTC−7, UTC−6 in summer).
Dial your exit code, then 1, then 307 and the seven-digit number: +1 307 XXX XXXX. Stored for a dialer or CRM, that is +1307XXXXXXX in E.164.
The area code says nothing on its own — spammers spoof local codes so the call looks familiar. In the FTC's complaint files since Aug 25, 2026, 588 different 307 numbers were reported. Check the exact number with the free lookup above.