In 1624 Sir Nicholas Rainton, a wealthy haberdasher and later Lord Mayor of London, purchased land in the area. Between 1629 and 1636, he built Forty Hall at the top of the hill, south of the medieval Elsyng Palace, which was demolished later in the 17th century. The name apparently derives from Sir Hugh Fortee, the owner prior to Sir Nicholas.
In 1951 the estate was purchased from Derek Parker Bowles by Enfield Urban District Council, who subsequently opened the grounds to the public and in 1962 began restoring the house and outbuildings. In 1966 Forty Hall was opened as a museum containing items of local historical interest. The house is surrounded by four hectares of ornamental grounds, the fragmentary remains of the 17th-century garden overlaid with 18th-century and later developments.