Norton Conyers, house and garden, have belonged to the Grahams since 1624.
Recent excavations have revealed that parts of the house are Anglo-Saxon.
The house's exterior has distinctive Dutch-style gables; its interior contains fine 18th century plaster ceilings in the principal rooms.
The garden is five minutes' walk from the house.
Laid out in the mid 18th century, it retains the essentials of its original design, together with sympathetic replanting in the English style.
Norton Conyers has a special atmosphere, resulting from 400 years of ownership by the Graham family.
Recent excavations beneath the house revealed evidence of a large Anglo-Saxon house.