ZIP Code 94028

94028 is one of California's ZIP codes, delivering to addresses in Portola Valley, San Mateo County.

City: Portola Valley
County: San Mateo County
State: California
Prefix: 940xx

Where this code sits

94028 is part of the 940xx range, the group of codes handled by one mail processing centre. It is the only ZIP code delivering to Portola Valley.

Portola Valley California ZIP codes →

Area codes over the same ground

Postal and telephone geography are drawn separately, so these codes cover the area 94028 delivers to without sharing its boundary.

650 Area code 650

ZIP codes nearest 94028

The ZIP codes whose reference points sit closest to 94028.
ZIP code	Distance	Delivers to
ZIP code 94304	4.7 mi	Palo Alto, CA
ZIP code 94305	4.8 mi	Stanford, CA
ZIP code 94025	5.1 mi	Menlo Park, CA
ZIP code 94022	5.1 mi	Los Altos, CA
ZIP code 94062	5.7 mi	Redwood City, CA
ZIP code 94023	5.8 mi	Los Altos, CA
ZIP code 94306	6.0 mi	Palo Alto, CA
ZIP code 94027	6.0 mi	Atherton, 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 94028, plotted from its record coordinates.

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

Scope ZIP code 94028. 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.