307 Area Code — Wyoming
307 is a North American Numbering Plan area code for Wyoming, the United States. It covers about 576,811 people in 156 towns and 175 ZIP codes, including Cheyenne, Casper and Gillette.
| Field | Value |
|---|---|
| Area code | 307 |
| Country | United States (+1) |
| State / province | Wyoming |
| Type | Standalone (no other NANP code covers the same towns) |
| Time zone | Mountain |
| Population covered | 576,811 |
| Towns covered | 156 |
| ZIP codes | 175 |
| Approx. centre | 42.824, -107.399 |
Where area code 307 is used
Area code 307 is assigned to Wyoming, the United States, inside the North American Numbering Plan. Numbers in the code are written (307) NXX-XXXX at home and +1 307 NXX-XXXX when dialled from outside Canada and the United States. Since the NANP moved to 10-digit dialling you must always include the area code, even for a local call.
Towns and cities in area code 307
The 156 towns below are the largest in the 307 footprint, ranked by population. Every one of them links to its own page with the full list of area codes and ZIP codes for that town.
| Town | County | Population | ZIP codes |
|---|---|---|---|
| Cheyenne | Laramie County | 94,953 | 8 |
| Casper | Natrona County | 72,922 | 5 |
| Gillette | Campbell County | 43,436 | 3 |
| Laramie | Albany County | 37,112 | 4 |
| Rock Springs | Sweetwater County | 27,198 | 2 |
| Sheridan | Sheridan County | 26,310 | 1 |
| Riverton | Fremont County | 19,413 | 1 |
| Jackson | Teton County | 17,445 | 2 |
| Cody | Park County | 16,582 | 1 |
| Evanston | Summit County | 14,435 | 2 |
| Lander | Fremont County | 13,266 | 1 |
| Powell | Park County | 12,337 | 1 |
Counties covered
| County | ZIP codes |
|---|---|
| Laramie County | 17 |
| Lincoln County | 15 |
| Big Horn County | 13 |
| Carbon County | 12 |
| Fremont County | 11 |
| Sweetwater County | 11 |
| Natrona County | 11 |
| Albany County | 8 |
| Goshen County | 8 |
| Sheridan County | 8 |
| Teton County | 8 |
| Crook County | 7 |
Nearby area codes
How to dial area code 307
- Within North America: 307 + 7-digit number (307-NXX-XXXX). The leading 1 is optional on a mobile phone and required on most landlines for long-distance.
- From abroad: your country's international prefix, then 1, then 307, then the 7-digit number — for example 00 1 307 NXX-XXXX from most of Europe.
Frequently asked questions
What area code is 307?
307 is a North American Numbering Plan area code assigned to Wyoming, the United States. It covers about 576,811 people in 156 towns.
Is 307 a US or Canadian area code?
307 is a United States area code. Canada and the United States share the +1 country code, so both are part of the same numbering plan.
What time zone is area code 307 in?
Area code 307 is in the Mountain time zone.
Do I have to dial 10 digits?
Yes. Every NANP call now requires the area code plus the seven-digit number, even for a local call.