North American Numbers Source-cited · ownership disclosed
Area code
720
In service
United States · since 1998

Denver (overlay)

Area code 720 is an all-services overlay of 303, instituted in 1998 to relieve number exhaustion in the fast-growing Denver-Boulder region. It shares the exact geography of 303 and 983.

The essentials Numbering data · NumberResearch · as of 2026-09-18
Place
Denver (overlay)
Type
geographic
Status
in service
In service since
1998
Projected exhaust
2069 Q2

Status, dates and counts are read from NumberResearch (NANPA / CNAC / FCC records). Assignment records show initial assignees, not the carrier serving a number today.

A · Where it is

Where 720 is

North-central Colorado: Denver, Boulder and surrounding Front Range suburbs..

Communities served wholly or partly by 720:

DenverBoulderAuroraLakewoodLittletonLongmontBroomfieldCastle Rock
B · Relationships

How it relates to other codes

The codes 720 was split from, spawned, or shares its area with. A split divides the map and changes some numbers; an overlay shares the same ground and changes none — what's the difference?

Overlay · 1998 303 Denver Overlays the original 303 Denver-Boulder area.
Overlay · 2022 983 Denver (overlay) Same geography; third code in the Denver-metro complex.
What's changing. Overlay — second code of the 303/720/983 Denver-metro overlay complex.
C · History

How 720 got here

1998-09-01
Instituted as an overlay of the 303 service area; ten-digit dialing required.
Source: Wikipedia
2022-06-17
Area code 983 activated, joining the 303/720 overlay.
Source: Wikipedia
D · Capacity

How full it is

Prefixes assigned
800
Prefixes available
0
Thousands-blocks assigned
5,561

Prefix-assignment counts describe allocation to carriers, not how many individual numbers are in use. Full technical records: NumberResearch ↗.

Compare 720 with another code →
Sources
Wikipedia ↗
Area code 720
NumberResearch.org ↗
Live status, dates, assignment counts and exhaust forecast — data as of 2026-09-18 (CC BY 4.0).

Place, relationships and history above are compiled by North American Numbers from the sources listed and last checked 2026-09-18. A check date is not an expert review — see how this is made. Flag an error.