First inhabited by Chumash Indians, in the late 19th century, the area became an agricultural center whose main produce was lemons. Most of the agricultural land gave way to development beginning with the arrival of Rocketdyne Jet Propulsion Laboratories in the 1950s and currently its makeup is comprised of residential areas along with many technology, service and light industries based in the city.
According to the United States Census Bureau, the city has a total area of 102.1 km² (39.4 mi²). 101.5 km² (39.2 mi²) of it is land and 0.6 km² (0.2 mi²) of it is water. The total area is 0.63% water.
As of the census of 2000, there are 111,351 people, 36,421 households, and 28,954 families residing in the city. The population density is 1,097.3/km² (2,841.9/mi²). There are 37,272 housing units at an average density of 367.3/km² (951.3/mi²). The racial makeup of the city is 81.33% White, 1.26% African American, 0.70% Native American, 6.33% Asian, 0.14% Pacific Islander, 6.50% from other races, and 3.74% from two or more races. 16.82% of the population are Hispanic or Latino of any race.
There are 36,421 households out of which 42.5% have children under the age of 18 living with them, 63.9% are married couples living together, 10.7% have a female householder with no husband present, and 20.5% are non-families. 14.7% of all households are made up of individuals and 4.9% have someone living alone who is 65 years of age or older. The average household size is 3.04 and the average family size is 3.33.
In the city the population is spread out with 28.4% under the age of 18, 7.9% from 18 to 24, 32.9% from 25 to 44, 23.1% from 45 to 64, and 7.6% who are 65 years of age or older. The median age is 35 years. For every 100 females there are 97.9 males. For every 100 females age 18 and over, there are 95.6 males.
The median income for a household in the city is $70,370, and the median income for a family is $75,140. Males have a median income of $51,003 versus $35,237 for females. The per capita income for the city is $26,586. 5.8% of the population and 3.9% of families are below the poverty line. Out of the total people living in poverty, 6.2% are under the age of 18 and 7.2% are 65 or older.