The large mansion on site, Great Barr Hall, had its beginnings in the 17th Century, but was remodelled both by Joseph Scott in 1777, and in the 19th century by various occupants.
The Lunar Society, an infomal group of leading engineers, industrialists, scientists and thinkers of the day met here in the early 1800s. the hospital colony for those with severe learning difficulties was opened after the first world war. Originally known as Great Barr Park Colony for the mentally defective, it was later re-named St Margarets Hospital.