Fairfield is a city in Jefferson County, Iowa. The population was 9,509 at the 2000 census. It is the county seat of Jefferson County. Fairfield lies at 41°0′26″N, 91°57′57″W (41.007166, -91.965910)GR1. The geography is typical of the great plains of the American Midwest: around the town is rolling farmland specializing in corn, soybeans and hogs. Running west-east through the town is U.S. Highway 34; the city of Burlington is to the east. North-South is Iowa Highway 1, leading north to Iowa City and south to the Missouri state border.

As of the censusGR2 of 2000, there were 9,509 people, 4,063 households, and 2,372 families residing in the city. The population density was 639.6/km˛ (1,657.4/mi˛). There were 4,463 housing units at an average density of 300.2/km˛ (777.9/mi˛). The racial makeup of the city was 94.35% White, 0.99% African American, 0.16% Native American, 2.53% Asian, 0.03% Pacific Islander, 0.73% from other races, and 1.21% from two or more races. Hispanic or Latino of any race were 2.64% of the population.