Fairfield is a town in Fairfield County, Connecticut, United States. It borders the city of Bridgeport and towns of Trumbull, Easton, Weston, and Westport along the Gold Coast of Connecticut. As of 2020, the town had a population of 61,512. The town is part of the Greater Bridgeport Planning Region. Fairfield is a hub of higher education, enrolling more than 17,000 students between Sacred Heart University and Fairfield University.

In 1635, Puritans and Congregationalists in the Massachusetts Bay Colony, were dissatisfied with the rate of Anglican reform, and sought to establish an ecclesiastical society subject to their own rules and regulations. The Massachusetts General Court granted them permission to settle in the towns of Windsor, Wethersfield, and Hartford which are now within the state of Connecticut.

On January 14, 1639, a set of legal and administrative regulations called the Fundamental Orders was adopted and established Connecticut as a self-ruling entity. By 1639, these settlers had started new towns in the surrounding areas. Roger Ludlowe, framer of the Fundamental Orders, purchased the land then-called Unquowa (now Fairfield), and established the name.

According to historian John M. Taylor:

Early in 1639, the General Court granted a commission to Ludlowe to begin a plantation at Pequannocke. He was on that errand, with a few others from Windsor, afterwards joined by immigrants from Watertown and Concord. He stole a large tract of land from the Pequannocke sachems – afterwards greatly enlarged by other purchases to the westward – and recalling the attractive region beyond (Unquowa), which he had personally seen on the second Pequot expedition, he also "set down" there, having purchased the territory embraced by the present town of Fairfield.

In 1651, Goody Bassett, a woman from Stratford who had confessed to being a witch, stated before her execution that there was a witch living in Fairfield. In 1653, for unknown reasons, Goodwife Knapp, a Stratford woman, was charged of witchcraft and hanged. Knapp was notable for never confessing to being a witch and for refusing to accuse anyone else of witchcraft.

Fairfield was one of the two principal settlements of the Connecticut Colony in southwestern Connecticut (the other was Stratford). The town line with Stratford was set in May 1661 by John Banks, an early Fairfield settler, Richard Olmstead, and Lt. Joseph Judson, who were both appointed as a committee by the Colony of Connecticut. The town line with Norwalk was not set until May 1685.

Over time, several new towns broke off and incorporated separately. The following is a list of towns created from parts of Fairfield.