Residential delivery area · California
ZIP Code 91789: Walnut, CA
ZIP code 91789 is in Walnut, California, entirely in Los Angeles County (Census 2020 ZIP-county file). About 40,000 people live there (Census Bureau, ACS 2020-2024). Median household income is $125,720 (Census Bureau, ACS 2020-2024). By Census place, its land lies in Walnut (56%), Industry (19%), Diamond Bar (12%) and Rowland Heights (11%), and 2% in smaller places; under 1% is outside any Census place.
- ACS2020-24
- Census2020
- FHFA2025
- ZBP2023
- IRS2022
- Town
- Walnut · its only residential ZIP
- County
- Los Angeles County
- Census places
- Walnut (56%); Industry (19%); Diamond Bar (12%); Rowland Heights (11%) census-designated place
- Neighborhood
- Walnut Hills Mobile Home Park GeoNames
- Metro area
- Los Angeles-Long Beach-Anaheim, CA
- House districts
- CA-38 (97%), CA-35 (2%) 119th Congress, by share of land
- State
- California
- Time zone
- Pacific
- Land area
- 15.9 sq mi · 2,540 people per sq mi
- PO Box ZIPs
- 91788 also use the name Walnut
Where is ZIP code 91789?
91789 centers on 34.018°, -117.855° and covers 15.9 square miles of land plus 0.1 of water. It borders 6 ZIP codes: 91792, 91765, 91791, 91748, 91724, 91768.
The map draws ZIP code areas only. For the streets inside 91789, open its center on OpenStreetMap.
Source: U.S. Census Bureau, 2020 ZCTA cartographic boundaries and the 2023 Gazetteer (2020 ZCTAs); ZIP-to-county shares, Census places and House districts (119th Congress) from the Census 2020 relationship files (shares of land); metro area from the OMB delineation (July 2023); town name and time zone from simplemaps US ZIP Codes (CC BY 4.0); neighborhoods from the GeoNames gazetteer (CC BY 4.0), placed in this ZIP code by PlainZIP.
How does 91789 compare with the rest of Los Angeles County?
| Measure | 91789 | In Los Angeles County | In CA |
|---|---|---|---|
| People (ACS 2020-2024) | 40,298 | 97th of 301 | 380th of 1,802 |
| Median household income | $126k | 49th of 265 | 312th of 1,189 |
| Median home value | $975k | 99th of 273 | 374th of 1,317 |
Its median household income is higher than in 92% of U.S. residential ZIP codes, and it is denser than 87% of all U.S. residential ZIP codes. ZIP codes at the ACS caps ($250,000 or more for household income, $2,000,000 or more for home value) share the top rank.
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B01003, B19013, B25077); ranks by PlainZIP over residential ZIP codes (ZCTAs).
How many people live in 91789?
The 2020 Census counted 41,235 people in 91789; the ACS, which samples households over 2020-2024, estimates 40,298. Between the 2010 and 2020 censuses its population fell 4.3% (its boundary stayed at least 90% the same).
- People, ACS 2020-2024
- 40,298
- 2020 Census count
- 41,235−4.3% since 2010 (43,079)
- Households
- 12,681
- Median age
- 46.3
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B01003, B01002, B11001); 2020 Census (DHC P1); 2010 Census (SF1 P1).
Who lives in 91789?
Of the 40,298 people the ACS estimates in 91789, 19.8% are under 18 and 22.3% are 65 or older. The largest group by race and Hispanic origin is Asian (not Hispanic) (67.0%), then Hispanic or Latino (18.1%).
- Under 1819.8%
- 18 to 6457.9%
- 65 and older22.3%
- Asian, not Hispanic67.0%
- Hispanic or Latino18.1%
- White, not Hispanic9.6%
- Other or two or more3.6%
- Black, not Hispanic1.7%
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B01001 age by sex, B03002 Hispanic or Latino origin by race); shares of the estimated population, small ZIP codes carry wide margins.
What do households in 91789 earn?
Median household income is $125,720 (ACS 2020-2024), the 49th highest of the 265 ranked ZIP codes in Los Angeles County. It is not measurably different from 2015-2019 ($124,958 in 2024 dollars): the change is within the surveys' margins of error.
- Median household income
- $125,720
- Income per person
- $49,392
- Below the poverty line
- 9.2%
- Unemployed (of the labor force)
- 4.4%
- Adults 25+ with a bachelor's degree
- 54.4%
- Adjusted gross income per tax return, 2022
- $117,31420,820 returns; wages 56% of AGI (IRS)
Source: U.S. Census Bureau, ACS 2020-2024 and 2015-2019 5-year estimates (B19013, B19301, B17001, B23025, B15003; 2015-2019 dollars converted with the BLS CPI-U, 1.22699); IRS Statistics of Income, ZIP code data, tax year 2022 (adjusted gross income per return, filed under the address on the return).
What are homes worth in 91789?
FHFA's house price index for 91789, built from repeat sales and appraisals of the same homes, rose 59% from 2015 to 2025 and rose 46% from 2020 to 2025, and moved +1.6% in 2025.
- Median home value (owners' estimate)
- $975,000
- Median gross rent
- $2,865
- Homes owned by their occupants
- 82.1%
- Housing units
- 13,503
Source: U.S. Census Bureau, ACS 2020-2024 5-year estimates (B25077, B25064, B25003, B25001); FHFA House Price Index, annual five-digit ZIP, updated 2026-03-31.
What businesses are in 91789?
2,325 business establishments had a location in this ZIP code in 2023, 186 more than in 2018; the most are in wholesale trade (ZIP Code Business Patterns).
- Wholesale trade513
- Professional, scientific, and technical services292
- Transportation and warehousing249
- Retail trade230
- Health care and social assistance173
- Real estate and rental and leasing152
Source: U.S. Census Bureau, ZIP Code Business Patterns 2023 and 2018 (establishments with paid employees, by the business's ZIP code).
Which ZIP codes are next to 91789?
| ZIP | Town | People | Household income | Distance |
|---|---|---|---|---|
| 91792 | West Covina | 30,629 | $95k | 2.7 mi |
| 91765 | Diamond Bar | 44,502 | $106k | 3.4 mi |
| 91791 | West Covina | 33,028 | $102k | 3.7 mi |
| 91748 | Rowland Heights | 42,463 | $83k | 3.9 mi |
| 91724 | Covina | 28,352 | $103k | 4.2 mi |
| 91768 | Pomona | 34,200 | $76k | 4.9 mi |
| 91744 | La Puente | 76,942 | $94k | 4.8 mi (near) |
| 91723 | Covina | 17,733 | $94k | 5.0 mi (near) |
Source: PlainZIP from the Census 2020 ZCTA boundaries (shared edges) and internal points; figures ACS 2020-2024.
Which other ZIP codes use the name Walnut?
1 more ZIP code carries the postal name Walnut, CA without a residential delivery area: PO boxes at the post office, or a single organization with its own ZIP code. The Census Bureau publishes no figures for it.
| ZIP | County |
|---|---|
| 91788 | Los Angeles County |
Source: GeoNames postal codes (CC BY 4.0), downloaded 2026-10-09; a ZIP code with no Census ZCTA has no residential delivery area.