Ontario is a city located in San Bernardino County, California. As of the 2000 census, the city had a total population of 158,007. It is the home of Ontario International Airport.
According to the United States Census Bureau, the city has a total area of 129.1 km² (49.9 mi²). 128.9 km² (49.8 mi²) of it is land and 0.2 km² (0.1 mi²) of it is water. The total area is 0.14% water.
As of the census of 2000, there are 158,007 people, 43,525 households, and 34,689 families residing in the city. The population density is 1,225.5/km² (3,173.9/mi²). There are 45,182 housing units at an average density of 350.4/km² (907.6/mi²). The racial makeup of the city is 47.83% White, 7.51% African American, 1.06% Native American, 3.88% Asian, 0.37% Pacific Islander, 34.05% from other races, and 5.30% from two or more races. 59.88% of the population are Hispanic or Latino of any race.
There are 43,525 households out of which 49.4% have children under the age of 18 living with them, 56.9% are married couples living together, 15.5% have a female householder with no husband present, and 20.3% are non-families. 15.1% 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 3.60 and the average family size is 3.96.
In the city the population is spread out with 34.4% under the age of 18, 11.2% from 18 to 24, 32.4% from 25 to 44, 16.1% from 45 to 64, and 5.9% who are 65 years of age or older. The median age is 28 years. For every 100 females there are 100.6 males. For every 100 females age 18 and over, there are 98.7 males.
The median income for a household in the city is $42,452, and the median income for a family is $44,031. Males have a median income of $31,664 versus $26,069 for females. The per capita income for the city is $14,244. 15.5% of the population and 12.2% of families are below the poverty line. Out of the total people living in poverty, 19.1% are under the age of 18 and 7.6% are 65 or older.