---
title: "Area code 720: Colorado, United States"
url: "https://lookvalid.com/area-code/720.md"
canonical_url: "https://lookvalid.com/area-code/720"
last_updated: "2026-10-23"
type: "reference"
summary: "Area code 720 serves Colorado, United States. Number formats, numbering rules, a live phone validator and the other codes in Colorado."
---

# Area code 720: Colorado, United States

Area code 720 serves Colorado, United States. Number formats, numbering rules, a live phone validator and the other codes in Colorado.

NANPA lists 785 central office codes (prefixes) in use in area code 720, held by 45 holders across 12 rate centers.
The largest rate center is DENVER, with 678 prefixes (86%).
T-Mobile USA holds the most prefixes, 132 (17%). 83% of the prefixes are pooled, which means their thousands-blocks can belong to different companies.
The FCC unwanted-call data has 6,366 complaints on file for 4,593 numbers in 720, most often filed as "Unwanted Calls". These are consumer reports, not findings.

## Facts

- In service since: 1998-06-01
- Time zone: Mountain (M)
- Assigned overlays: 303 (1947-01-01), 983 (2022-06-17)
- Prefixes in use: 785
- Pooled prefixes: 653 (83%)
- Rate centers: 12
- Companies holding prefixes: 45
- Assignment dates on file: 2001-01-12 to 2024-09-03 (508 prefixes)
- ZIP codes in its places: 78

## Rate centers

| Rate center | Prefixes | Share |
| --- | --- | --- |
| DENVER | 678 | 86% |
| LONGMONT | 39 | 5% |
| FORTLUPTON | 14 | 2% |
| GEORGETOWN | 11 | 1% |
| ALLNSPKLYN | 10 | 1% |
| DECKERS | 10 | 1% |
| KEENESBURG | 9 | 1% |
| HUDSON | 8 | 1% |
| 4 other rate centers | 6 | <1% |

## Carriers

| Holder | Prefixes | Share |
| --- | --- | --- |
| T-Mobile USA | 132 | 17% |
| Qwest | 103 | 13% |
| New Cingular Wireless PCS | 92 | 12% |
| Verizon Wireless | 75 | 10% |
| Bandwidth.com CLEC | 55 | 7% |
| Onvoy | 55 | 7% |
| 39 other carriers | 273 | 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 303, named as the parent of 720 in the NANPA report, was in service.
- 1998-06-01: Area code 720 went into service.

## Nearest area codes

The area codes closest to 720, measured between the centers of the ZIP code places they serve, are 970 (about 61 miles), 719 (about 111 miles), 307 (about 235 miles), 308 (about 254 miles) and 505 (about 298 miles).

## ZIP codes

78 ZIP codes fall in places that have a rate center in this area code. The places with the most are Denver, CO (66 ZIP codes), Longmont, CO (4 ZIP codes) and Bennett, CO (1 ZIP code). 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

6,366 complaints for 4,593 numbers. Numbers whose latest complaint falls in each year:

- 2023: 232
- 2024: 230
- 2025: 265

## Questions

### Where is area code 720?

NANPA assigns area code 720 to Colorado, United States.

### In which state does area code 720 sit?

Colorado. 720 is one of 6 area codes the NANPA table assigns to the state.

### Which places does area code 720 cover?

The places with the most ZIP codes among the rate centers in 720 are Denver, CO, Longmont, CO and Bennett, CO. The rate center list on this page shows all of them.

### Who owns area code 720?

NANPA assigns area codes. Within 720, T-Mobile USA holds the most prefixes, 132 prefixes or 17%.

### Which time zone does 720 use?

The NANPA NPA report lists the time zone for 720 as Mountain (M).

### What year did 720 enter service?

The NANPA NPA report gives an in-service date of 1998-06-01, so 720 has been in use since 1998.

### Does area code 720 have an overlay?

Yes. 303 (in service 1947-01-01) and 983 (in service 2022-06-17) share the same area with 720, so numbers from all of them are local to each other.

### Which area codes are nearest to 720?

The area codes closest to 720, measured between the centers of the ZIP code places they serve, are 970 (about 61 miles), 719 (about 111 miles), 307 (about 235 miles), 308 (about 254 miles) and 505 (about 298 miles).

### How many prefixes does area code 720 have?

NANPA's report dated 2026-10-17 lists 785 prefixes in service in 720, spread over 12 rate centers and 45 holders.

### Are there complaints about 720 numbers?

The FCC data on file has 6,366 complaints for 4,593 numbers in 720. 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).