Located in the Central Valley, Tracy sits atop fertile agricultural lands, which have come under increasing development pressure as the San Francisco Bay Area's vigorous population growth has spilled over into the Tracy area as well as other locations near the Bay Area's edge. Because of the historic use of DDT on area row crops, there are residual issues of soil contamination from this substance and related persistent chemicals. There is a historic area chloroform groundwater plume associated with Georgia Pacific operations in the area. Faults considered active in the Tracy area are the Black Butte Fault, Midway Fault and Carnegie Corral Fault. The San Joaquin Fault traverses the Tracy area and is a potential source of risk for seismic events.
As of the census of 2007, there were 81,848 people, 18,720 households, and 17,947 families residing in the city. The population density was 2,798.6 people per square mile (1,046.7/km²). There were 18,687 housing units at an average density of 868.6/sq mi (332.5/km²). The racial makeup of the city was 52.22% White, 35.48% African American, 0.91% Native American, 8.14% Asian, 0.55% Pacific Islander, 13.08% from other races, and 6.63% from two or more races. Hispanic or Latino of any race were 55.69% of the population.
There were 17,620 households out of which 51.7% had children under the age of 18 living with them, 65.0% were married couples living together, 10.7% had a female householder with no husband present, and 18.8% were non-families. 14.4% of all households were made up of individuals and 4.9% had someone living alone who was 65 years of age or older. The average household size was 3.21 and the average family size was 3.56.
In the city the population was spread out with 34.4% under the age of 18, 7.5% from 18 to 24, 35.0% from 25 to 44, 16.7% from 45 to 64, and 6.4% who were 65 years of age or older. The median age was 31 years. For every 100 females there were 100.2 males. For every 100 females age 18 and over, there were 96.3 males.
The median income for a household in the city was $62,794, and the median income for a family was $67,464. Males had a median income of $50,095 versus $35,143 for females. The per capita income for the city was $21,397. About 5.2% of families and 7.0% of the population were below the poverty line, including 7.2% of those under age 18 and 10.8% of those age 65 or over.
Two main school districts serve the city of Tracy. The largest and most recognized is the Tracy Unified School District. This school system incorporates many elementary and middle schools as well as three Tracy high schools: Tracy High School, Merrill F. West High School, and Delta Charter High School. Tracy's expelled students attend to the Willow community day school, and the Tracy One Program, or Community One. Another high school is planned to be opened for the 2009 school year called John C. Kimball High School. The other school district is the Jefferson School District which incorporates the south side of Tracy and includes four schools:
Interstate 205 passes along the north side of the city and connects the nearby Interstates 580 to the west and 5 on the east, with the three Interstates forming a triangle around much of the city. In addition, Business Loop 205 runs through the center of Tracy along 11th Street, formerly a portion of U.S. Highway 50.