720 area code — Denver, CO geographic
The 720 area code covers Denver, Colorado, Mountain time zone, and dates back to June 1, 1998. The same territory is also served by its overlay codes (303/720/983 complex). Keep in mind the code identifies where the number was registered; the person calling may be elsewhere.
The code currently holds 785 working prefixes, held by 46 different carriers. Of these, 653 are pooled prefixes shared by multiple carriers. Numbers are anchored to 12 rate centers — billing localities that fix where each prefix belongs.
The current NANPA exhaust forecast for the 303/720/983 complex is 2Q 2069.
Local calls inside 720 are dialed 10D; 1+10 permissible at service providers discretion.
Use this page to decode where 720 numbers come from — and remember that spoofing means the screen can lie about everything except your own caution.
The code was carved out of 303 (1998).
Largest localities in 720
| Locality (rate center) | Active prefixes | Also served by |
|---|---|---|
| Denver | 678 | 303, 983 |
| Longmont | 39 | 303, 983 |
| Fort Lupton | 14 | 303, 983 |
| Georgetown | 11 | 303 |
| Allenspark-lyons | 10 | 303 |
| Deckers | 10 | 303, 983 |
| Keenesburg | 9 | 303 |
| Hudson | 8 | 303 |
| Deer Trail | 3 | 303 |
| Strasburg | 1 | 303, 983 |
FAQ
Will 720 run out of numbers?
NANPA's current forecast projects exhaust in 2Q 2069 — decades of capacity remain.
Why am I getting spam calls from 720 numbers?
Scammers spoof recognizable area codes so calls look local or familiar. A displayed 720 number does not prove the call originated there — see our guide to spotting spoofed calls.
Where is a 720 number from?
720 is assigned to Denver and surrounding areas of Colorado in the Mountain time zone. The three digits after the area code (the prefix) narrow it down to a rate center.
Is 720 a toll-free number?
No. 720 is a geographic code; calls are billed like any other domestic call. Toll-free codes are 800, 833, 844, 855, 866, 877 and 888.
Why do 303 and 720 cover the same place?
They are overlays: when a code runs low on numbers, a new code is added over the same territory instead of splitting it. The 303/720/983 complex shares one service area, and local calls are dialed with 10 digits.