New Haven is the second-largest municipality in Connecticut (after Bridgeport and ahead of Hartford) and the sixth-largest municipality in New England with a core population of 129,779 people as of the 2010 Census. "New Haven" may also refer to the wider Greater New Haven area, which has nearly 600,000 inhabitants in the immediate area. It is located in New Haven County, on New Haven Harbor, on the northern shore of Long Island Sound.

One year after its founding in 1638, eight streets were laid out in a grid of four streets by four streets creating what is now commonly known as the "Nine Square Plan," which is recognized by the American Institute of Certified Planners as a National Historic Planning Landmark. The central common block is New Haven Green a 16-acre (6 ha) square, now a National Historic Landmark and the center of Downtown New Haven.