The village of Stanmer, Stanmer House and Stanmer Church are within the park, which would once have been the estate of the house. All were private until bought by Brighton's Council in 1947. It is a Local Nature Reserve.
Today the park is open to the public, and there is a café in the village. Guided walks of the woods are sometimes available, and in particular, "bat walks" where attendees are shown the considerable local bat population. There is also a plant nursery in the old walled kitchen garden of the estate. It has been producing plants for local parks since the 1950s.
The etymological root of the name is "Stony Mere", referring to the stones around the village pond.
The house was built in 1722 around an even earlier one. It was built for the Pelham family who lived there and developed the estate over many years. A mistress of King George IV also lived there. It reopened in June 2006 after extensive restoration and is now available to hire for weddings and functions. It was used as the first administrative centre of the 1961 University of Sussex, during the construction of its campus over a part of the park. A walk of elm trees was preserved within the campus design, by architect Sir Basil Spence. It is open to the public on Tuesdays.
The church, adjacent to the village pond, was built in 1838 on the site of a 14th-century building. The church is now maintained by the Stanmer Preservation Society, which also runs Stanmer Rural Museum and the Donkey Wheel.
The woods beyond the park to the north and west lead into Wild Park and the open South Downs countryside, part of the South Downs National Park. Immediately to the south of the park runs the major A27 road.
English Heritage, under the National Heritage Act 1983, registered the park on the Register of Parks and Gardens of Special Historic Interest in England at Grade II level.
The Park also has one of Britain's few Earthships