Walnut zipcode
| City | Walnut |
| ZIP Code | 91789 |
| Type | Standard |
| State Code | CA |
| State | California |
ZIP code of Walnut is 91789. This place is located in California state in US. To send any postal service to Walnut, you must use 91789 zipcode.
The ZIP code 91789 is also used with 3 more city names of California.
- City Industry, CA
- City Of Industry, CA
- Diamond Bar, CA