Wiston House is a 16th-century Grade I listed building set in the South Downs National Park on the south coast of England, surrounded by over 6,000 acres (2,400 ha) of parkland in Wiston, West Sussex. It is the home of Wilton Park, an executive agency of the Foreign and Commonwealth Office.
Originally built in two storeys to an irregular floor plan, substantial parts of the house have since been demolished and replaced and additional wings added. It is a Grade I listed building.[1]