ZIP Code 94509

94509 is one of California's ZIP codes, delivering to addresses in Antioch, Contra Costa County.

City: Antioch
County: Contra Costa County
State: California
Prefix: 945xx

Where this code sits

94509 is part of the 945xx range, the group of codes handled by one mail processing centre. Antioch is served by 2 ZIP codes in total; the full list, with the county each falls in, is on the Antioch page.

Antioch California ZIP codes →

Area codes over the same ground

Postal and telephone geography are drawn separately, so these codes cover the area 94509 delivers to without sharing its boundary.

ZIP codes nearest 94509

The ZIP codes whose reference points sit closest to 94509.
ZIP code	Distance	Delivers to
ZIP code 94531	2.6 mi	Antioch, CA
ZIP code 94561	5.7 mi	Oakley, CA
ZIP code 94565	5.9 mi	Pittsburg, CA
ZIP code 94517	7.7 mi	Clayton, CA
ZIP code 94513	7.8 mi	Brentwood, CA
ZIP code 94548	8.0 mi	Knightsen, CA
ZIP code 94527	8.6 mi	Concord, CA
ZIP code 94511	9.3 mi	Bethel Island, CA

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 94509, plotted from its record coordinates.

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

Scope ZIP code 94509. 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.