Formally incorporated in 1903, the city of Fairfield is the seat of Solano County. Major industries include food and beverage, back office/technical operations, bio tech, and medical supplies. The largest employer is Travis Air Force Base. The Base includes approximately 7,393 active military personnel, 3,692 civilians, and 3,257 reservists, and has a local annual economic impact of $1 billion. Travis is home to the 60th Air Mobility Wing, the largest air mobility organization in the Air Force, and the 349th Air Mobility Wing, the largest associate wing in the United States Air Force Reserve. Travis Air Force Base is also a crucial base of operations for American humanitarian aid abroad. Interstates 680 and 80, several bus services, and California Northern Railroad connect goods and people to the broader region.

According to the 2008 U.S. Census Department estimate, 103,683 people live in Fairfield. According to the 2000 Census, the city of Fairfield is 56.2 percent White, 15 percent Black, 10.9 percent Asian, 0.8 percent American Indian and Alaska Native, and 0.9 percent Native Hawaiian or Other Pacific Islander. 18.8 percent of Fairfield residents are of Latino or Hispanic origin, and 7.4 percent of residents report being of two or more races.