Green River, Wyoming, is served by area code 307. Whether you are calling a Green River number, verifying an unknown caller, or setting up a new local line, this guide covers every area code that serves the city, how local dialing works, the ZIP codes involved, and the scam-call patterns residents report most often.
Green River Area Codes at a Glance
| Detail | Information |
|---|---|
| Primary Area Code | 307 |
| Overlay Code | None currently active |
| Time Zone | Mountain Time (MT, UTC-7 / UTC-6) |
| Major Counties | Sweetwater County |
| State | Wyoming |
Area Code Breakdown & Neighborhood Mapping
Green River sits in the high desert of southwestern Wyoming, which is served entirely by area code 307. A single area code has covered this area without needing a split or overlay, so a 307 number reads clearly as a local line.
Within the city, 307 covers downtown along the Green River, the Expedition Island area, and the residential neighborhoods serving the trona-mining industry. Nearby communities in the same region include Rock Springs, Evanston.
Across Wyoming, 307 connects to the rest of the state through standard long-distance dialing, and every call to or from Green River follows the same North American Numbering Plan rules used nationwide. Knowing which code covers the city helps you spot out-of-area numbers at a glance and recognize when an incoming call may not be as local as it appears.
Local Dialing Rules & International Calling
Like the rest of the United States, Green River uses 10-digit dialing. Dial the area code plus the seven-digit number for local calls. For domestic long distance, add a leading 1 (1 + 307 + number). To call Green River from another country, dial your country’s exit code, then the U.S. country code +1, then the area code and the local number. Mobile users can enter +1 307 directly. Three-digit services such as 911 for emergencies and 988 for the Suicide and Crisis Lifeline are always dialed directly, with no area code required.
Major ZIP Codes in Green River
Green River’s primary ZIP code is 82935, which covers the city and much of the surrounding western Sweetwater County area.
Cell Phones & Number Portability
Thanks to federal number portability, a 307 number no longer proves the caller is currently in Green River. Residents who move away often keep their mobile numbers, and newcomers frequently arrive with codes from other states. New local service is typically assigned a 307 number, but the reliable habit is to dial all ten digits every time and to judge callers by who they are rather than by the area code they display.
Spam & Scam Call Warnings in Green River
Green River residents report the same robocall trends seen across Wyoming. Watch for these patterns:
- Neighbor spoofing: Scam calls that fake a 307 prefix so the number looks local. Screen unfamiliar callers even when the area code matches.
- Utility shutoff threats: Callers posing as the power or water company demanding immediate payment by gift card or wire. Real utilities never work this way.
- Government impersonation: Fake IRS, Social Security, or county “warrant” calls pressuring you to pay to avoid arrest.
- Local angle: In this southwestern Wyoming city, watch for fake-employment and utility-shutoff scams, including callers demanding immediate payment to avoid a service disconnection.
- Auto-warranty and Medicare pitches: High-volume robocalls seeking personal, financial, or insurance details, often using a recorded voice and a callback number.
Let unknown calls go to voicemail, never share financial information with an inbound caller, and report unwanted calls to the FTC at reportfraud.ftc.gov.
Frequently Asked Questions
What area code does Green River use?
Green River uses area code 307.
Do I have to dial the area code for local calls?
Yes. Green River uses 10-digit dialing, so include the area code even for calls within the city.
What county is Green River in?
Green River is located in Sweetwater County.
What time zone is Green River in?
Green River observes Mountain Time (MT, UTC-7 / UTC-6).
How do I call Green River from another country?
Dial your exit code, then +1, then 307 and the seven-digit local number.
Does the area code affect the cost of a call?
No. Call costs depend on your calling plan, not on the 307 area code. Most U.S. mobile and landline plans include nationwide calling, so reaching a Green River number is treated the same as any other domestic call.
Can I keep my phone number if I move to Green River?
Usually yes. Federal number portability lets you keep an existing mobile number when you relocate, which is why many Green River residents carry numbers with area codes from other cities or states.
Stay Safe & Explore More
- Verify an unknown caller in our Scam Alerts directory.
- Comparing nationwide numbers? See our Toll-Free Numbers guides.