Fairfield is a city in, and the
county seat of,
Jefferson County,
Iowa,
United States. It has a population totaling 9,464 people according to the
2010 census. It is a Midwestern city surrounded by rolling farmlands filled with corn, soybean, cattle, and hogs with a median family income of $46,138 (10% of families below the
poverty line). The city became the county seat in 1839 with 110 residents and grew to 650 by 1847. Its library was established in 1853, and it held its first fair in 1854. Early architecture includes work by
George Franklin Barber and
Barry Byrne, who trained under
Frank Lloyd Wright.