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 Code
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).
In service since: 01-Jun-1998
Demographics & Economics
- Total Population
- 5,264,773
- Population Density
- 298 people/sq miabove U.S. average (U.S.: 93 people/sq mi)
- Median Household Income
- $97,215above U.S. median (U.S.: $75,144)
- Poverty Rate
- 8.6%below U.S. average (U.S.: 11.5%)
- Unemployment Rate
- 4.3%above U.S. average (U.S.: 3.6%)
- Education Attainment
- Bachelor's Degree+48.6%above U.S. average (U.S.: 33.7%)High School or Lower21.6%
Statistics are population-weighted aggregations from Census ACS 5-year estimates. Population figures are approximate — see Sources & Methodology for details on how area code populations are derived.
See how this area code compares to all US area codes in the income ranking and density ranking.
Time Zone
- Mountain Time (MT)
NANPA Relief Status
According to the latest NANPA analysis (July 2026), this area code is not currently listed as exhausting within the next 36 months. No relief planning is in progress for this NPA.
Source: NANPA NPA Relief Planning Reports · See all relief planning statuses
Current Time
Prefix Utilization
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
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 93. The median household income is $97,215, which is higher than the national median of $75,144. Approximately 48.6% of adults hold a bachelor's degree or higher, compared to the national rate of 33.7%. This rate is higher than the national average. The poverty rate stands at 8.6%, which is lower than the national rate of 11.5%.
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.
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% |
Area Code 720 Family Tree
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Area code 720 was originally assigned in 01-Jun-1998 to serve CO.
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.