Founded in 1869 by Kentuckian William H. Spurgeon on land purchased from the Yorba family, Santa Ana was incorporated as a city in 1886 with a population of 2000 and in 1889 became the seat of the newly formed Orange County.
According to the United States Census Bureau, the city has a total area of 71.0 km² (27.4 mi²). 70.3 km² (27.1 mi²) of it is land and 0.7 km² (0.3 mi²) of it is water. The total area is 0.95% water.
As of the census of 2000, there are 337,977 people, 73,002 households, and 59,788 families residing in the city. The population density is 4,808.2/km² (12,451.9/mi²). There are 74,588 housing units at an average density of 1,061.1/km² (2,748.0/mi²). The racial makeup of the city is 42.73% White, 1.70% African American, 1.19% Native American, 8.81% Asian, 0.34% Pacific Islander, 40.64% from other races, and 4.58% from two or more races. 76.07% of the population are Hispanic or Latino of any race.
There are 73,002 households out of which 53.2% have children under the age of 18 living with them, 60.6% are married couples living together, 13.5% have a female householder with no husband present, and 18.1% are non-families. 12.7% of all households are made up of individuals and 4.6% have someone living alone who is 65 years of age or older. The average household size is 4.55 and the average family size is 4.72.
In the city the population is spread out with 34.2% under the age of 18, 12.8% from 18 to 24, 34.1% from 25 to 44, 13.5% from 45 to 64, and 5.5% who are 65 years of age or older. The median age is 26 years. For every 100 females there are 107.7 males. For every 100 females age 18 and over, there are 108.7 males.
The median income for a household in the city is $43,412, and the median income for a family is $41,050. Males have a median income of $23,342 versus $21,637 for females. The per capita income for the city is $12,152. 19.8% of the population and 16.1% of families are below the poverty line. Out of the total people living in poverty, 24.1% are under the age of 18 and 10.4% are 65 or older.