ZIP Code 94552

94552 is one of California's ZIP codes, delivering to addresses in Castro Valley, Alameda County.

City: Castro Valley
County: Alameda County
State: California
Prefix: 945xx

Where this code sits

94552 is part of the 945xx range, the group of codes handled by one mail processing centre. Castro Valley is served by 2 ZIP codes in total.

Area codes over the same ground

Postal and telephone geography are drawn separately, so these codes cover the area 94552 delivers to without sharing its boundary.

ZIP codes nearest 94552

The ZIP codes whose reference points sit closest to 94552.
ZIP code	Distance	Delivers to
ZIP code 94546	2.3 mi	Castro Valley, CA
ZIP code 94542	3.8 mi	Hayward, CA
ZIP code 94543	3.8 mi	Hayward, CA
ZIP code 94541	3.9 mi	Hayward, CA
ZIP code 94578	4.8 mi	San Leandro, CA
ZIP code 94544	5.5 mi	Hayward, CA
ZIP code 94580	5.5 mi	San Lorenzo, CA
ZIP code 94583	5.6 mi	San Ramon, 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 94552, plotted from its record coordinates.

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

Scope ZIP code 94552. 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.