Great Fosters is a 16th-century mansion which originally lay within Windsor Great Park and is still adjacent to the town of Egham, Surrey, England. It is a Grade I listed building, close to Heathrow and the M25 London orbital motorway. The formal gardens of Great Fosters were laid out in 1918 by W. H. Romaine-Walker in partnership with G. H. Jenkins, the pair also extended the house.