New Haven is a city in the U.S. state of Connecticut. It is located on New Haven Harbor on the northern shore of Long Island Sound. With a population of 134,023 at the 2020 census, it is the third-most populous city in Connecticut and the largest in the South Central Connecticut Planning Region, with the Greater New Haven metropolitan area having an estimated 577,000 residents.
New Haven was one of the first planned cities in the U.S. A year after its founding by English Puritans in 1638, eight streets were laid out in a three-by-three grid, creating the "Nine Square Plan". The central common block is the New Haven Green, a 16-acre (6 ha) square at the center of Downtown New Haven. The Green is now a National Historic Landmark, and the "Nine Square Plan" is recognized by the American Planning Association as a National Planning Landmark.