ZIP Code 94528

94528 is one of California's ZIP codes, delivering to addresses in Diablo, Contra Costa County.

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

Where this code sits

94528 is part of the 945xx range, the group of codes handled by one mail processing centre. It is the only ZIP code delivering to Diablo.

Area codes over the same ground

Postal and telephone geography are drawn separately, so these codes cover the area 94528 delivers to without sharing its boundary.

925 Area code 925

ZIP codes nearest 94528

The ZIP codes whose reference points sit closest to 94528.
ZIP code	Distance	Delivers to
ZIP code 94526	1.7 mi	Danville, CA
ZIP code 94506	2.8 mi	Danville, CA
ZIP code 94507	3.2 mi	Alamo, CA
ZIP code 94570	4.3 mi	Moraga, CA
ZIP code 94575	4.3 mi	Moraga, CA
ZIP code 94583	5.8 mi	San Ramon, CA
ZIP code 94582	5.9 mi	San Ramon, CA
ZIP code 94517	6.1 mi	Clayton, 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 94528, plotted from its record coordinates.

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

Scope ZIP code 94528. 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.