Guilford is a town in New Haven County, Connecticut, United States, that borders Madison, Branford, North Branford and Durham, and is situated on I-95 and the Connecticut seacoast. The population was 22,375 at the 2010 census. In 2015 the population stands at approximately 22,413 people.
Guilford was named after the town of Guildford, in England, the native home of a share of its first settlers. In early maps of the Connecticut Colony, the town is seen on several maps as Gilford.
First settled by Europeans in 1639 after being purchased from Native American leader Wequash, Guilford is considered by some to have the third largest collection of historic homes in New England, with important buildings from the 17th, 18th, and 19th centuries. There are five historic house museums, including Dudley Farm and the Henry Whitfield House (1639), the oldest dwelling house in Connecticut and the oldest stone house built by English settlers in North America. The Comfort Starr House (1645–46) is one of the oldest wooden framed private dwellings in Connecticut, and one of the few houses remaining of the original signers who settled Guilford.
In June 1781, during the American Revolution, a skirmish was fought on Leete's Island between the Associated Loyalists and local militia under Captain Peter Vail.
According to the United States Census Bureau, the town has a total area of 49.7 square miles (129 km2), of which 47.0 square miles (122 km2) is land and 2.7 square miles (6.9 km2 or 5.39%) is water.
The primary settlement in Guilford, known as Guilford Center, is located in the southern part of town around the intersection of U.S. Route 1 and Connecticut Route 77.