Red Hook is a neighborhood in western Brooklyn, New York City, New York, within the area once known as South Brooklyn. It is located on a peninsula projecting into the Upper New York Bay and is bounded by the Gowanus Expressway and the Carroll Gardens neighborhood on the northeast, Gowanus Canal on the east, and the Upper New York Bay on the west and south. A prosperous shipping and port area in the early 20th century, the area declined in the latter part of the century. Today it is home to the Red Hook Houses, the largest housing project in Brooklyn.

South Brooklyn is a historic term for a section of the former City of Brooklyn – now the New York City borough of Brooklyn – encompassing what are now the Boerum Hill, Carroll Gardens, Cobble Hill, Gowanus, Park Slope, Windsor Terrace, Sunset Park and Red Hook neighborhoods. It was named for its location along the waterfront that was the southern border of the original Village of Brooklyn, and has remained widely used as a colloquialism despite it no longer being the southernmost point of the borough. It should not be confused with the geographic southern region of the modern borough of Brooklyn, which includes the neighborhoods of Gravesend, Seagate, Coney Island, Brighton Beach, Manhattan Beach, Sheepshead Bay, Gerritsen Beach, Marine Park, Mill Basin, and Bergen Beach.