ZIP Code 80503

80503 is one of Colorado's ZIP codes, delivering to addresses in Longmont, Boulder County.

City: Longmont
County: Boulder County
State: Colorado
Prefix: 805xx

Where this code sits

80503 is part of the 805xx range, the group of codes handled by one mail processing centre. Longmont is served by 4 ZIP codes in total; the full list, with the county each falls in, is on the Longmont page.

Longmont Colorado ZIP codes →

Area codes over the same ground

Postal and telephone geography are drawn separately, so these codes cover the area 80503 delivers to without sharing its boundary.

ZIP codes nearest 80503

The ZIP codes whose reference points sit closest to 80503.
ZIP code	Distance	Delivers to
ZIP code 80502	3.3 mi	Longmont, CO
ZIP code 80501	3.6 mi	Longmont, CO
ZIP code 80544	3.6 mi	Niwot, CO
ZIP code 80533	4.1 mi	Hygiene, CO
ZIP code 80301	7.8 mi	Boulder, CO
ZIP code 80516	8.3 mi	Erie, CO
ZIP code 80540	10 mi	Lyons, CO
ZIP code 80542	10 mi	Mead, CO

Straight-line distance between place reference points, not driving distance. Where a place has no Census Gazetteer point, its postal centroid is used instead.

Each point is the reference point for 80503, plotted from its record coordinates.

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

Scope ZIP code 80503. Source GeoNames US postal codes (2026-07 postal dump) and Census 2024 county Gazetteer (2024 Gazetteer). Updated 15 July 2026. A ZIP code is a set of delivery routes, not an area; the point shown is a record coordinate, not a centre.