As of the census of 2000, there were 121,780 people, 44,020 households, and 30,329 families residing in the city. The population density was 4,041.0 people per square mile (1,560.0/km²). There were 45,083 housing units at an average density of 1,496.0/sq mi (577.5/km²). The racial makeup of the city is 70.71% White, 3.04% Black or African American, 0.76% Native American, 9.39% Asian, 0.50% Pacific Islander, 9.65% from other races, and 5.94% from two or more races. 21.81% of the population are Hispanic or Latino of any race.
There were 44,020 households out of which 34.4% had children under the age of 18 living with them, 51.4% were married couples living together, 12.3% had a female householder with no husband present, and 31.1% were non-families. 23.2% of all households were made up of individuals and 7.2% had someone living alone who was 65 years of age or older. The average household size was 2.74 and the average family size was 3.22.
In the city the age of the population was spread out with 25.3% under the age of 18, 9.0% from 18 to 24, 32.8% from 25 to 44, 22.2% from 45 to 64, and 10.7% who were 65 years of age or older. The median age was 35 years. For every 100 females there were 97.6 males. For every 100 females age 18 and over, there were 95.3 males.
The median income for a household in the city was $55,597, and the median income for a family was $62,093. Males had a median income of $45,734 versus $34,860 for females. The per capita income for the city was $24,727. About 5.2% of families and 7.6% of the population were below the poverty line, including 9.0% of those under age 18 and 6.2% of those age 65 or over.
As of 2005, the racial makeup of the city had changed to: 63.9% White, 2.6% Black or African American, 0.1% Native American, 12.0% Asian, 0.8% Pacific Islander, 15.4% from other races, and 5.2% from two or more races. 26.3% of the population were Hispanic or Latino of any race.
Until 1995 the city was the eastern terminus of the Concord line of Bay Area Rapid Transit (BART) commuter train system; the line has since been extended eastward to Pittsburg/Bay Point. The County Connection provides limited public transportation in the city and to other points in the county. Buses run from the North Concord BART station to Martinez, the county seat.
Main thoroughfares include Willow Pass Road, Concord Avenue, Concord Boulevard, Clayton Road, Ygnacio Valley Road and Treat Boulevard. The city is also served by Interstate 680, and state highways 4 and 242.
Buchanan Field Airport is a public county-owned airfield in the City of Concord. It currently does not have any scheduled passenger service, but was once served by Pacific Southwest Airlines as well us U.S. Airways for a short time.