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US area code · Wyoming

Area code 307

Where the 307 area code is, its overlay and how to dial a +1 307 number from anywhere.

CoversCasper, WyomingTime zoneMountain (MT)TypeGeographic
Quick answer

The 307 area code is in Casper, Wyoming, United States (Mountain (MT)). To call from abroad: +1 307 555-0123.

StateWyoming
Main areaCasper
Time zoneMountain (MT)
TypeGeographic
10-digit dialingNot required
In service since01-Jan-1947

The 307 area code is a geographic North American Numbering Plan (NANP) code covering Casper, Wyoming. It has been in service since 01-Jan-1947 and sits in the Mountain (MT) time zone.

How to dial a 307 number

From abroad+1 307 555-0123
Within the US / Canada1 307 555-0123

Cities in the 307 area code

A 307 number is usually in one of these places in Wyoming — 4 counties.

Casper NatronaCheyenne LaramieGillette CampbellLaramie Albany

Frequently asked questions

Where is the 307 area code?

The 307 area code is in Casper, Wyoming, United States (Mountain (MT)).

Do I have to dial 10 digits for 307?

Local calls within 307 may use seven digits; ten-digit dialling always works.

How do I call a 307 number from another country?

Dial your exit code (or +), then 1, then 307, then the number: +1 307 555-0123.

Source: NANPA numbering plan. An area code covers a region, not a precise address — a 307 number does not pinpoint a street or ZIP code.

Missed a call from +1 307?

In the 30 days to September 24, 2026, 392 unwanted calls showing a 307 number were reported to the US Federal Trade Commission, 63% of them recorded messages or robocalls. That puts 307 at #250 of 670 area codes reported.

Other151
Reducing your debt (credit cards, mortgage, student loans)137
Calls pretending to be government, businesses, or family and friends20
Dropped call or no message16
Before you call back
  • If you do not know anyone in Wyoming, do not call back: a genuine caller will leave a message or send a text.
  • Scammers fake the number shown on caller ID, so a 307 number can hide a caller anywhere in the world.
  • Never give a code received by text or a bank detail to an unknown caller. In the US, calls can be reported at reportfraud.ftc.gov.

Who issues +1 307 numbers

Phone companies hold blocks of numbers in each area code. The main holders in 307:

Qwest Corporation 83Union Telephone Company 65Cellco Partnership Dba Verizon Wireless 60New Cingular Wireless PCS, LLC 49Onvoy, LLC 40Level 3 Communications, LLC 27

About 23.6% of the 525 prefixes in use belong to mobile carriers: a 307 number is often a cell phone, and it may have moved to another carrier since.

Sources: FTC Do Not Call reported calls (numbers as reported by consumers, not verified), NANPA central office code assignments.

All US area codes United States +1 Map of area code 307 — cities & rate centres