According to the United States Census Bureau, the CDP has a total area of 1.6 square miles (4.1 km²), all of it land.
As of the census of 2000, there were 3,903 people, 1,160 households, and 881 families residing in the CDP. The population density was 2,463.7 people per square mile (953.8/km²). There were 1,214 housing units at an average density of 766.3/sq mi (296.7/km²). The racial makeup of the CDP was 65.92% White, 0.54% African American, 1.46% Native American, 1.82% Asian, 0.20% Pacific Islander, 24.62% from other races, and 5.43% from two or more races. Hispanic or Latino of any race were 42.89% of the population.
There were 1,160 households out of which 39.0% had children under the age of 18 living with them, 52.6% were married couples living together, 16.3% had a female householder with no husband present, and 24.0% were non-families. 20.6% of all households were made up of individuals and 9.1% had someone living alone who was 65 years of age or older. The average household size was 3.30 and the average family size was 3.77.
In the CDP the population was spread out with 31.6% under the age of 18, 10.3% from 18 to 24, 27.4% from 25 to 44, 19.8% from 45 to 64, and 10.9% who were 65 years of age or older. The median age was 32 years. For every 100 females there were 95.5 males. For every 100 females age 18 and over, there were 89.5 males.
The median income for a household in the CDP was $27,500, and the median income for a family was $30,862. Males had a median income of $28,814 versus $22,750 for females. The per capita income for the CDP was $12,133. About 16.5% of families and 21.8% of the population were below the poverty line, including 25.1% of those under age 18 and 22.2% of those age 65 or over.
In the state legislature Empire is located in the 12th Senate District, represented by Republican Jeff Denham, and in the 25th Assembly District, represented by Republican Tom Berryhill. Federally, Empire is located in California's 18th congressional district, which has a Cook PVI of D +3 and is represented by Democrat Dennis Cardoza.