ZIP Code 91788 is located in Walnut California. 91788 is entirely within Los Angeles County. Regionally, it is located in Metro Los Angeles.
| ZIP Code Name | Walnut |
| Primary County | Los Angeles County |
| ZIP Code Type | PO Box |
| Current Time | PDT |
| Coordinates | 34.01202393,-117.86074829 |
| Adjacent ZIP Codes | |
| Region | Metro Los Angeles |
| Metropolitan/Micropolitan Stat Area | Los Angeles-Long Beach-Anaheim, CA |
| Time Zone | Pacific Daylight Time |
| IANA Timezone | America/Los_Angeles |