The 307 area code covers Cheyenne, Casper and 71 more places in Wyoming.
Area code 307 is in Wyoming, on Mountain Time. In the 307 area, phone numbers are given out most in Laramie County, then Natrona and Fremont counties. It has been in service since 1947.
- Where
- 8 counties in Wyoming, mostly Laramie County, Natrona County and Fremont County
- Time zone
- Mountain Time
- In service since
- 1947, one of the original area codes
- Shares its area with
- No other area code
- Prefixes in use
- 499
- How to dial
- Local calls inside 307 can still be dialed with just 7 digits.
Find out who called you from a 307 number.
Enter the full 10-digit number to see who it is listed to and the city and state on the listing. It is the same free check as our who called me lookup. To see only the caller ID name on the number, use our free CNAM lookup. To see whether it is a mobile, a landline or a VoIP line, use our free VoIP checker. To see which carrier a (307) number is on today, use our free carrier lookup.
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Cheyenne holds 12% of the phone prefixes in area code 307.
A prefix is the three digits after the area code, and NANPA assigns each one to a town. Counting the 499 prefixes in use shows where 307 numbers are actually given out.
- Cheyenne60 prefixes, 12%
- Casper40 prefixes, 8%
- Jackson21 prefixes, 4%
- Gillette21 prefixes, 4%
- Laramie18 prefixes, 4%
- Rock Springs17 prefixes, 3%
- Sheridan17 prefixes, 3%
- Cody15 prefixes, 3%
Also served: Riverton, Evanston, Lander and Powell and 61 smaller places.
Qwest (Lumen) holds the most phone number prefixes in area code 307: 83 of 499.
NANPA, which runs the North American numbering plan, assigns each prefix (the three digits after the area code) to one carrier. Here is how the 499 prefixes in use in 307 divide between carriers; holders this page does not name are grouped as other carriers.
| Carrier | Prefixes | Share |
|---|---|---|
| Qwest (Lumen)Lumen's landline company | 83 | 17% |
| Union Telephone | 76 | 15% |
| AT&T MobilityMobile network | 49 | 10% |
| Level 3 (Lumen)Lumen's business and wholesale network | 27 | 5% |
| BandwidthSupplies numbers to VoIP and app-based phone services | 19 | 4% |
| RT Communications | 17 | 3% |
| 41 other carriers | 228 | 46% |
56% of these prefixes are pooled, which means the blocks of 1,000 numbers inside them can belong to other carriers. Any number can also have been moved to another carrier since, so this shows who holds the prefixes, not who serves a given number.
Want the carrier of one exact number? Our free carrier lookup checks it, because numbers move between carriers.
Source: NANPA central office code assignments, October 1, 2026.
307 has covered the same ground since 1947.
1947
307 is one of the original North American area codes.
A 307 number on your screen can still be a scam, because caller ID is easy to fake.
- Let an unknown call go to voicemail. A real caller leaves a message; a robocaller usually does not.
- Look the number up with the box above before you call back, because calling back tells a robocaller your line is live.
- Hang up on anyone who wants gift cards, crypto or a wire transfer, or asks you to read out a code that was just texted to you.
- Report unwanted robocalls at reportfraud.ftc.gov, or paste a suspicious message into our free scam checker.
The area codes closest to 307 are 970.
This list measures the distance between the centres of each area, across state lines, and shows codes that share one area together.
These are the questions people ask most about area code 307.
Where is area code 307?
307 covers Cheyenne, Casper, Jackson and Gillette and 69 more places in Wyoming. In the 307 area, phone numbers are given out most in Laramie County, then Natrona and Fremont counties.
What state is area code 307 in?
Wyoming. 307 is a Wyoming area code on Mountain Time.
What cities use area code 307?
The places holding the most 307 prefixes are Cheyenne, Casper, Jackson, Gillette, Laramie, Rock Springs, Sheridan and Cody, out of 73 places in all. The count comes from NANPA's prefix assignments as of October 1, 2026.
Which phone company owns area code 307?
No single phone company owns 307. NANPA's records show Qwest (Lumen) holds the most 307 prefixes, 83 of 499, followed by Union Telephone and AT&T Mobility. Numbers move between carriers, so check one exact number with a carrier lookup.
What time zone is area code 307 in?
307 is on Mountain Time.
When did area code 307 start?
307 is one of the original North American area codes, in service since 1947.
How do I dial a 307 number?
Local calls inside 307 can still be dialed with just 7 digits.
Is 307 a toll-free number?
No. 307 is a regular area code for Cheyenne and Casper in Wyoming, not a toll-free one. The toll-free codes in North America are 800, 833, 844, 855, 866, 877 and 888.
What area codes are near 307?
The closest are 970/748 (Fort Collins, Colorado), measured between the centres of each area.
Who called me from a 307 number?
Enter the full 10-digit number in the lookup above. It returns the listed owner where there is a public record, where the number is registered, and whether it is a mobile, a landline or a VoIP line.
Is area code 307 a scam?
307 is a real Wyoming area code, so the code itself is not a warning sign. Scam callers fake local-looking numbers on purpose, so judge the call by what the caller asks for, and look the number up before calling back.
Put this lookup on your site: our free area code widget takes two lines of code and shows any US area code's state, time zone and local time.
Source: NANPA, the North American Numbering Plan Administrator: its area code database and prefix assignments, as of October 1, 2026.