Zip Code Lookup - Hayward, Alameda county California
| City | ZipCode | Area Code(s) | County | state | Time Zone | MSA |
| Castro Valley (Castro Valley Zip Code Lookup) | 94552 (94552 Zip Code Lookup) | 510 | Alameda | California | Pacific | 5775 |
| Hayward (Hayward Zip Code Lookup) | 94552 (94552 Zip Code Lookup) | 510 | Alameda | California | Pacific | 5775 |