From the Wikipedia page 
An area of open space within Richmond-upon-Thames, England, and is 90.37 hectares (223.3 acres) in extent. The park is bounded generally by the River Thames to the west, Kew Gardens to the north, and urban areas of Richmond town to the east and south. Owned by the Crown Estate, the park forms part of a larger historic landscape stretching from Richmond to Kew and across the river to Isleworth. The majority of Old Deer Park is occupied by the Royal Mid-Surrey Golf Club, and this has been so since the late nineteenth century. Within the club's boundaries are two eighteen-hole courses, plus a separate area within which lies the Grade I listed Kew Observatory, established by King George III in 1769. To the SW of the Observatory, under the fairway of the 14th hole of the golf course, lie the foundations of the former Carthusian Sheen Priory, founded by Henry V in 1414. The low-lying parts of the park alongside the river constitute flood storage areas, which from time-to-time provide flood relief for areas around Richmond Lock along this stretch of the Thames.