Manchester Square is an 18th-century garden square in the Marylebone area in London, England, a short distance north of Oxford Street. It is one of the smaller but better preserved Georgian squares in central London. The central section of the northern side of the square is occupied by a mansion once known as Manchester House and later as Hertford House, which is now the home of the Wallace Collection, a major collection of fine and decorative arts. The house and square form part of Marylebone's Portman Estate.