General Law city
Incorporated: January 19, 1959
City Hall: 21201 La Puente Rd, Walnut, California 91789
Population (2020 Census): 28,430 (Also see latest State Population Estimates and Earlier decennial Census Counts).
Population Under Age 18 (2020 Census): 17.1%
Population Density (2020 Census): 3,162.8 persons per square mile
Housing Units: 9,169
Persons Per Housing Unit: 3.1
Land Area: 8.99 square miles (23.28 square kilometers)
Water Area: 0.00 square miles (0.01 square kilometers)
Total Area: 8.99 square miles (23.28 square kilometers)
Geographic Coordinates (Latitude/Longitude): 34.037195 -117.855606
The local post office was originally called Lemon due to its location on Lemon Road. The name was changed to Walnut in 1912, probably because of the negative slang use of the word lemon.
City in red below. Click on map for more detailed color map of county.