San Joaquin is a city in Fresno County, California, United States. The population was 3,270 at the 2000 census. The nearest high school in the area is Tranquillity High School in Tranquillity. San Joaquin is located 11 miles (18 km) southwest of Kerman, at an elevation of 174 feet (53 m).
According to the United States Census Bureau, the city has a total area of 1.0 square miles (2.6 km²), all of it land.
As of the census of 2000, there were 3,270 people, 702 households, and 636 families residing in the city. The population density was 3,302.4 people per square mile (1,275.3/km²). There were 735 housing units at an average density of 742.3/sq mi (286.7/km²). The racial makeup of the city was 35.44% White, 0.21% Black or African American, 1.56% Native American, 3.61% Asian, 53.73% from other races, and 5.44% from two or more races. 91.99% of the population were Hispanic or Latino of any race.
There were 702 households out of which 67.9% had children under the age of 18 living with them, 70.9% were married couples living together, 12.5% had a female householder with no husband present, and 9.3% were non-families. 6.7% of all households were made up of individuals and 4.1% had someone living alone who was 65 years of age or older. The average household size was 4.66 and the average family size was 4.79.
In the city the population was spread out with 41.2% under the age of 18, 14.2% from 18 to 24, 27.9% from 25 to 44, 12.7% from 45 to 64, and 4.0% who were 65 years of age or older. The median age was 22 years. For every 100 females there were 113.6 males. For every 100 females age 18 and over, there were 114.3 males.
The median income for a household in the city was $24,934, and the median income for a family was $25,441. Males had a median income of $20,382 versus $16,023 for females. The per capita income for the city was $6,607. About 33.9% of families and 34.6% of the population were below the poverty line, including 41.1% of those under age 18 and 23.7% of those age 65 or over.