Colorado Area Codes

Area codes: 6
ZIP codes: 645
Cities & towns: 399
Counties: 64

Every area code in Colorado

All Colorado area codes, what each primarily serves, and which share ground with another.
Area code	Primarily serves	Shares ground with	In service
303	Denver	720, 983	1947
719	Colorado Springs	no overlay	1988
720	Denver	303, 983	1998
748	Fort Collins	970	2025
970	Fort Collins	748	1995
983	Denver	303, 720	2022

A code in the “shares ground” column is an overlay: it covers the same territory rather than a different part of Colorado, which is why local calls there are dialled as ten digits.

Which codes share the same ground

Colorado has 2 groups of codes that overlay one another: the codes inside a group cover the same territory rather than different parts of the state, so local calls there are dialled as ten digits.

303 720 983
748 970

719 has no overlay: it is the only code serving its territory.

Where Colorado's communities sit

Each point is a Colorado community, plotted from its record coordinates. The outline is the convex envelope of those points — a footprint, not a boundary.

Reference points and footprint
Not an official NANPA boundary
Not a USPS delivery area

Largest Colorado cities and their codes

largest 25

Scope every area code assigned to Colorado. Source LocalCallingGuide NPA list (2026-07 NPA list) and geoinfo-dataset (full_dataset) ZIP→NPA (2018 snapshot). Updated 16 July 2026. Overlay relationships come from the numbering-plan authority; the city match is computed.