---
title: "Area code 307: Wyoming, United States"
url: "https://lookvalid.com/area-code/307.md"
canonical_url: "https://lookvalid.com/area-code/307"
last_updated: "2026-10-23"
type: "reference"
summary: "Area code 307 serves Wyoming, United States. Number formats, numbering rules, a live phone validator and the other codes in Wyoming."
---

# Area code 307: Wyoming, United States

Area code 307 serves Wyoming, United States. Number formats, numbering rules, a live phone validator and the other codes in Wyoming.

NANPA lists 497 central office codes (prefixes) in use in area code 307, held by 52 holders across 92 rate centers.
Qwest holds the most prefixes, 83 (17%). 56% of the prefixes are pooled, which means their thousands-blocks can belong to different companies.
The FCC unwanted-call data has 2,968 complaints on file for 2,086 numbers in 307, most often filed as "Unwanted Calls". These are consumer reports, not findings.

## Facts

- In service since: 1947-01-01
- Time zone: Mountain (M)
- Prefixes in use: 497
- Pooled prefixes: 277 (56%)
- Rate centers: 92
- Companies holding prefixes: 52
- Assignment dates on file: 2001-01-29 to 2026-03-31 (232 prefixes)
- ZIP codes in its places: 86

## Rate centers

| Rate center | Prefixes | Share |
| --- | --- | --- |
| CHEYENNE | 60 | 12% |
| CASPER | 40 | 8% |
| GILLETTE | 21 | 4% |
| JACKSON | 21 | 4% |
| LARAMIE | 18 | 4% |
| ROCK SPG | 17 | 3% |
| SHERIDAN | 17 | 3% |
| CODY | 15 | 3% |
| 84 other rate centers | 288 | 58% |

## Carriers

| Holder | Prefixes | Share |
| --- | --- | --- |
| Qwest | 83 | 17% |
| Union Telephone Company | 65 | 13% |
| Verizon Wireless | 60 | 12% |
| New Cingular Wireless PCS | 49 | 10% |
| Onvoy | 40 | 8% |
| Level 3 Communications | 27 | 5% |
| 46 other carriers | 173 | 35% |

A prefix holder is the company a code was assigned to, not necessarily a number's current carrier, because numbers can be ported to another company.

## History

- 1947-01-01: Area code 307 went into service.

## Nearest area codes

The area codes closest to 307, measured between the centers of the ZIP code places they serve, are 970 (about 227 miles), 303 (about 235 miles), 720 (about 235 miles), 983 (about 235 miles) and 385 (about 283 miles).

## ZIP codes

86 ZIP codes fall in places that have a rate center in this area code. The places with the most are Cheyenne, WY (8 ZIP codes), Casper, WY (5 ZIP codes) and Laramie, WY (4 ZIP codes). A ZIP code and an area code are unrelated systems, so a ZIP code can sit in more than one area code and an area code spans many ZIP codes.

## Complaints on file

2,968 complaints for 2,086 numbers. Numbers whose latest complaint falls in each year:

- 2023: 80
- 2024: 95
- 2025: 86

## Questions

### Where is area code 307?

NANPA assigns area code 307 to Wyoming, United States.

### In which state does area code 307 sit?

Wyoming. 307 is one of 1 area code the NANPA table assigns to the state.

### Which places does area code 307 cover?

The places with the most ZIP codes among the rate centers in 307 are Cheyenne, WY, Casper, WY and Laramie, WY. The rate center list on this page shows all of them.

### Who owns area code 307?

NANPA assigns area codes. Within 307, Qwest holds the most prefixes, 83 prefixes or 17%.

### Which time zone does 307 use?

The NANPA NPA report lists the time zone for 307 as Mountain (M).

### What year did 307 enter service?

The NANPA NPA report gives an in-service date of 1947-01-01, so 307 has been in use since 1947.

### Does area code 307 have an overlay?

The NANPA NPA report lists no other area code in an overlay with 307.

### Which area codes are nearest to 307?

The area codes closest to 307, measured between the centers of the ZIP code places they serve, are 970 (about 227 miles), 303 (about 235 miles), 720 (about 235 miles), 983 (about 235 miles) and 385 (about 283 miles).

### How many prefixes does area code 307 have?

NANPA's report dated 2026-10-17 lists 497 prefixes in service in 307, spread over 92 rate centers and 52 holders.

### Are there complaints about 307 numbers?

The FCC data on file has 2,968 complaints for 2,086 numbers in 307. They are unverified consumer reports. A number with no complaints on file is not proven safe.

Sources: NANPA central office code report dated 2026-10-17; NANPA NPA report dated 2026-10-18; FCC unwanted-call complaints, data fetched 2026-10-17; ZIP code places from GeoNames (CC BY 4.0).