Wyoming · Mountain Time
307 Area Code
Area code 307 is in Wyoming, serving the entire state of Wyoming. It is in the Mountain Time zone.
Last updated October 1, 2026 · Source: NANPA
Where is the 307 area code?
307 is a Wyoming area code covering the entire state of Wyoming. In the wider directory it sits in the West region.
Cities in the 307 area code
- Cheyenne
- Casper
- Gillette
- Laramie
- Rock Springs
- Sheridan
- Green River
- Evanston
- Riverton
- Jackson
- Cody
- Rawlins
- Lander
- Torrington
Counties served by 307
Laramie County, Natrona County, Campbell County, Albany County, Sweetwater County, Sheridan County, Fremont County, Park County, Teton County and Uinta County.
Dialing 307
Cheyenne, WY is currently served by the single area code 307, with no overlay. Ten-digit dialing (area code + seven-digit number) always works and is increasingly the norm nationwide; some local calls may still connect with seven digits. If a future overlay is added, 10-digit dialing would become mandatory.
From outside the US, dial +1 307 followed by the seven-digit number.
History of the 307 area code
307 went into service on January 1, 1947. It serves Cheyenne and the surrounding part of Wyoming. For how codes are created, split, and overlaid, see how area codes work.
Is 307 a scam or spam risk?
307 is a legitimate geographic area code, not a premium or toll line, so a call from it costs you nothing extra. That said, scammers frequently spoof real local area codes to look familiar on caller ID. A genuine 307 number on your screen is no guarantee the caller is in Cheyenne, WY or trustworthy. See spam & scam-risk area codes for how spoofing works and how to respond.
Explore more
See every code in Wyoming, compare codes across the West region, or view all Mountain Time codes. You can also browse the 3XX block or the complete numeric list of US area codes.
New to how this all works? Start with how area codes work, then read up on overlays, 10-digit dialing, and spam & scam-risk codes. To check another number, use the area code lookup tool.
Quick answers
307 area code FAQ
Where is the 307 area code?
The 307 area code is in Wyoming, covering the entire state of Wyoming, in the West region.
What cities are in the 307 area code?
Cities in the 307 area code include Cheyenne, Casper, Gillette, Laramie, Rock Springs, Sheridan, Green River, Evanston, Riverton and Jackson.
What time zone is 307 in?
307 is in the Mountain Time zone.
When did the 307 area code start?
307 went into service on January 1, 1947.
Do I have to dial 10 digits for 307?
Ten-digit dialing always works, and many areas now require it; some local calls in this area may still connect with seven digits.
Is 307 a toll-free or premium code?
No. 307 is a standard geographic area code, so calling it costs the same as any local or long-distance call on your plan. Toll-free calls use 800, 888, 877, 866, 855, 844 or 833.