Union City California ZIP Codes
Union City holds a single ZIP code.
Every ZIP code in Union City
| ZIP code | County |
|---|---|
| 94587 | Alameda County |
We do not publish a delivery type (standard, PO box, unique) or a neighbourhood for each ZIP. USPS delivery-type products are licensed, and no clean-rights source maps ZIP codes to neighbourhoods — so the Union City codes above are listed without a column we would have to invent.
Scope every ZIP code recorded for Union City. Source GeoNames US postal codes (2026-07 postal dump) and Census 2024 county Gazetteer (2024 Gazetteer). Updated . ZIP codes are delivery-route groupings, not areas; the boundaries implied by any ZIP map are approximations.
How these codes cluster
Every Union City ZIP code begins 945. Those first three digits identify the sectional center facility that processes mail for this part of California. Statewide that range covers 93 ZIP codes, so Union City accounts for 1% of it.
Every California ZIP prefix and the region it covers →
Area codes covering Union City
ZIP codes and area codes are separate systems — one routes mail, the other routes calls — and they do not share boundaries. The codes below serve the same ground Union City occupies.
Union City California area codes in full →
Where Union City's ZIP codes sit
- Reference points and footprint
- Not an official NANPA boundary
- Not a USPS delivery area
Cities near Union City
| City | Distance | ZIP codes |
|---|---|---|
| Hayward California ZIP codes | 4.9 mi | 7 ZIP codes |
| Newark California ZIP codes | 6.8 mi | 1 ZIP code |
| Fremont California ZIP codes | 8.6 mi | 5 ZIP codes |
| Pleasanton California ZIP codes | 8.7 mi | 2 ZIP codes |
| Dublin California ZIP codes | 10 mi | 1 ZIP code |
| San Leandro California ZIP codes | 11 mi | 3 ZIP codes |
| Menlo Park California ZIP codes | 11 mi | 2 ZIP codes |
| San Ramon California ZIP codes | 12 mi | 2 ZIP codes |
Straight-line distance between place reference points, not driving distance.