720 Area Code — Denver, CO
Area code 720 serves Denver and 3 other cities in Colorado. Local time follows America/Denver. It overlays with 303, so 10-digit dialling is required.
- State
- Colorado
- Primary city
- Denver
- Timezone
- America/Denver
- In service since
- 1998
- Type
- Overlay
- Overlay codes
- 303
Overlay of 303
Cities Served by 720
The 720 area code covers 4 cities and communities in Colorado.
- Denver
- Aurora
- Lakewood
- Boulder
About Area Code 720
Area code 720 is a North American Numbering Plan (NANP) area code that has been in service since 1998. It is administered by NANPA on behalf of the FCC and serves the Colorado region anchored on Denver.
720 is an overlay code, which means it shares its geographic boundaries with one or more existing area codes (303). Overlays are created when a region exhausts the supply of phone numbers in its original area code. Within an overlay region, residents must dial all 10 digits even for local calls, because the same 7-digit number can exist under multiple area codes.
Mobile numbers in 720 are portable: a person who moved away from Denver may still carry a 720 mobile number on their device. If you receive an unexpected call from a 720 number, run it through the reverse lookup tool above for the most accurate, free identification.
If you live or do business in Colorado, you may also interact with neighbouring or overlay codes (303). See the related codes section below to explore the rest of Colorado.
Other Colorado Area Codes
Continue exploring the Colorado numbering plan.
720 Area Code FAQ
Where is area code 720?
Area code 720 is located in Colorado, primarily serving Denver and surrounding cities including Aurora, Lakewood, Boulder. The region operates on MT (America/Denver) time.
What state is 720 area code?
720 is a Colorado area code. It was put into service in 1998 as an overlay and shares its geographic footprint with overlay code 303.
Is 720 a scam area code?
720 is a legitimate North American area code allocated by NANPA to Colorado. Like any geographic area code, scammers sometimes spoof 720 numbers — judge each call by content (urgent demands, unfamiliar transfers) rather than the area code alone. Run the specific number through our reverse lookup if you're unsure.
What time zone does 720 use?
Area code 720 operates on MT (America/Denver). Numbers in this area code follow standard Colorado time-zone rules including any daylight-saving transitions for that region.
Can I look up a specific 720 phone number?
Yes. Use the reverse lookup widget above to enter a full 720 number. NumLocation returns the line type (mobile, landline, VoIP), carrier, rate-center city, and any public listings tied to the number — free.
What's the difference between 720 and 303?
720 and 303 cover the same Colorado geographic area as overlay codes. Calls between them are local, but you must dial all 10 digits. New phone numbers in this region are assigned from either pool depending on what's available with the carrier at signup.