Zip Code 91789 — Walnut, CA
91789 is a ZIP Code associated with Walnut, CA, located within Los Angeles. The postal region supports an estimated population of 40,298 residents across Data Pending housing units, with a population density of 980.6 people per square mile.
WorldPlaceData database updated: October 2026
📍 View location on OpenStreetMap (34.018580, -117.854080)
| Data Metric | Local Statistic |
|---|
| Postal / Zip Code | 91789 |
| Primary City | Walnut |
| State / Province | CA |
| County | Los Angeles |
| Total Population | 40,298 |
| Median Household Income | Data Pending |
| Total Housing Units | Data Pending |
| Population Density | 980.6 people/sq mi |
| Timezone | America/Los_Angeles |
How 91789 Compares
| Metric | ZIP 91789 | Los Angeles County | CA State Average |
|---|
| Population | 40,298 | 9,807,501 | 39,286,245 |
| Median Income | Data Pending | N/A | N/A |
| Population Density | 980.6 /sq mi | -- | -- |
Nearby ZIP Codes
Data Sources & Methodology: Geographic coordinates and ZIP Code assignments are derived from underlying geographic and postal datasets. Note that ZIP Codes are USPS postal delivery areas, while Census ZCTAs are statistical approximation areas. Read full methodology →