The Ninth Square Historic District encompasses a historically diverse and well-preserved part of the commercial area of Downtown New Haven, Connecticut. The district is bounded by Church, Court, State, and Crown Streets, and is centered on the intersection of Chapel and Orange Streets. The buildings in the district are mostly late-19th and early 20th commercial buildings, and includes a number of commercial buildings from the first half of the 19th century, a rarity in most of Connecticut's urban downtown areas. The district was listed on the National Register of Historic Places in 1984.