Area Code 720
Colorado
Area code 720 serves Colorado, primarily Denver, in the Mountain Time (MT) time zone. It is an overlay area code sharing territory with area code 303.
Overlay Area Codes
This area code is part of an overlay region, meaning the same geographic area is served by multiple area codes. Overlay codes were introduced to meet growing demand for phone numbers without requiring existing customers to change their numbers.
This area code shares its geographic region with: area code 303 (Denver), area code 983 (Denver).
In service since: 01-Jun-1998
Demographics
The estimated population served by area code 720 is approximately 5,264,773. The population density is 298 people per square mile, which is higher than the national average of 94. The median household income is $97,215, which is higher than the national median of $78,538. Approximately 48.6% of adults hold a bachelor's degree or higher, compared to the national rate of 35.0%. This rate is higher than the national average. The poverty rate stands at 8.6%, which is lower than the national rate of 12.4%.
History
Area code 720 serves as an overlay for the same territory as area code 303. It was introduced in 1998 to provide additional phone number capacity for the region. It shares its territory with area codes area code 303 and area code 983.
Demographics & Economics
- Total Population
- 5,264,773
- Population Density
- 298 people/sq miabove U.S. average (U.S.: 94 people/sq mi)
- Median Household Income
- $97,215above U.S. median (U.S.: $78,538)
- Poverty Rate
- 8.6%below U.S. average (U.S.: 12.4%)
- Unemployment Rate
- 4.3%below U.S. average (U.S.: 5.2%)
- Education Attainment
- Bachelor's Degree+48.6%above U.S. average (U.S.: 35.0%)High School or Lower21.6%
Statistics are population-weighted aggregations from Census ACS 5-year estimates.See Sources for details.
Geographic Coverage
State
CO
Major Cities
- Denver
- Aurora
- Lakewood
- Thornton
- Arvada
- Westminster
- Centennial
- Boulder
- Highlands Ranch
- Longmont
- Loveland
- Castle Rock
- Broomfield
- Commerce City
- Parker
- Littleton
- Brighton
- Northglenn
- Dakota Ridge
- Englewood
- Ken Caryl
- Wheat Ridge
- Erie
- Lafayette
and 124 more cities
Time Zone
- Mountain Time (MT)
Current Time
County Coverage
Population-weighted county share based on aggregated ZCTA population (100% = total mapped population for area code 720).
| County | Population | Share |
|---|---|---|
| Denver, CO | 1,044,485 | 19.8% |
| Arapahoe, CO | 989,106 | 18.8% |
| Adams, CO | 854,477 | 16.2% |
| Jefferson, CO | 762,712 | 14.5% |
| Douglas, CO | 502,657 | 9.5% |
| Boulder, CO | 458,086 | 8.7% |
| Broomfield, CO | 214,846 | 4.1% |
| Weld, CO | 193,758 | 3.7% |
| Larimer, CO | 102,131 | 1.9% |
| Elbert, CO | 65,901 | 1.3% |
| Clear Creek, CO | 30,425 | 0.6% |
| Gilpin, CO | 29,241 | 0.6% |
| Park, CO | 12,498 | 0.2% |
| El Paso, CO | 4,450 | 0.1% |
Call Context
This area code covers a geographic region across CO, including Denver and surrounding communities.
Nearby Area Codes
Area codes geographically closest to 720.
Other Area Codes in Colorado
Area codes that also serve Colorado, linked for easy comparison.
Frequently Asked Questions
Common questions about area code 720 and how phone numbering works.
Phone numbers assigned to area code 720 are tied to where they were originally provisioned — not the caller's current location. This code serving roughly 5265k people covers Denver in CO, so a number originally set up there will retain the 720 prefix even if the owner moves or uses VoIP. Mobile phones keep their original number when users relocate, and businesses often adopt local area codes to establish a regional presence.
Start by looking up the area code on this site to understand its geographic context — area code 720 is associated with Denver in CO. For caller-specific details, use your carrier's caller ID features or check public directories. If you suspect fraud, you can report it to the FTC. To file a complaint about robocalls or spoofed numbers, visit the FCC Consumer Complaint Center. You can also register with the National Do Not Call Registry.
When an area's available number pool runs low, regulators introduce an "overlay" code covering the same territory. Both codes coexist, and new numbers are assigned from whichever has availability. Area code 720 serves the Denver region in CO, where growing demand for phone numbers necessitated an additional code. This area code shares its region with area code 303, area code 983. Learn more in our overlay vs split guide.