Walnut Grove is a census-designated place (CDP) in Sacramento County, California, United States. It is part of the Sacramento–Arden-Arcade–Roseville Metropolitan Statistical Area. The population was 1,542 at the 2010 census, up from 669 at the 2000 census.
Walnut Grove is located at (38.243490, −121.512100).
According to the United States Census Bureau, the CDP has a total area of , of which, of it is land and of it (6.62%) is water.
The 2010 United States Census reported that Walnut Grove had a population of 1,542. The population density was . The racial makeup of Walnut Grove was 943 (61.2%) White, 15 (1.0%) African American, 24 (1.6%) Native American, 110 (7.1%) Asian, 0 (0.0%) Pacific Islander, 402 (26.1%) from other races, and 48 (3.1%) from two or more races. Hispanic or Latino of any race were 673 persons (43.6%).
The Census reported that 1,533 people (99.4% of the population) lived in households, 9 (0.6%) lived in non-institutionalized group quarters, and 0 (0%) were institutionalized.
There were 585 households, out of which 182 (31.1%) had children under the age of 18 living in them, 293 (50.1%) were opposite-sex married couples living together, 56 (9.6%) had a female householder with no husband present, 41 (7.0%) had a male householder with no wife present. There were 35 (6.0%) unmarried opposite-sex partnerships, and 4 (0.7%) same-sex married couples or partnerships. 165 households (28.2%) were made up of individuals, and 66 (11.3%) had someone living alone who was 65 years of age or older. The average household size was 2.62. There were 390 families (66.7% of all households); the average family size was 3.23.
The population was spread out, with 357 people (23.2%) under the age of 18, 137 people (8.9%) aged 18 to 24, 376 people (24.4%) aged 25 to 44, 432 people (28.0%) aged 45 to 64, and 240 people (15.6%) who were 65 years of age or older. The median age was 40.6 years. For every 100 females, there were 112.1 males. For every 100 females age 18 and over, there were 113.9 males.