Ashdown House (also known as Ashdown Park) is a 17th-century country house in the civil parish of Ashbury in the English county of Oxfordshire. Until 1974 the house was in the county of Berkshire, and the nearby village of Lambourn remains in that county.
Ashdown House is associated with the "Winter Queen" Elizabeth of Bohemia, the sister of Charles I. Along with his house at Hamstead Marshall, it is said that the William, the first Earl of Craven built Ashdown for her, but she died in 1662 before construction began.
Although the architect is uncertain, it is thought that Craven commissioned Captain William Winde to build the Dutch-style mansion as a hunting lodge and refuge from the plague. The house features 8,000 square feet (740 m2) of living space, a large central staircase, reception rooms, interlinking drawing and sitting rooms, a kitchen, a dining room and eight bedrooms. The property includes two lodges, three cottages and a hundred acres of land. The house is isolated, and the view from the roof includes park-like grounds and gardens, and beyond, woods and pastures. Nearby is a large group of sarsen stones and Alfred's Castle, an Iron Age hill fort.
At least one of the woods of Ashdown Park predates the house. Glastonbury Abbey held the manor of Ashbury until the Dissolution of the Monasteries in 1539. A deer park was established for the Abbey in the south of the parish. It is bounded by an ancient embankment enclosing a rounded area characteristic of Medieval deer parks. The embankment would have been topped by a park pale, probably of cleft oak stakes. The park may equate to the Aysshen Wood that a terrier of the parish in 1519 recorded as covering 415 acres (168 ha). The former deer park is now the Upper Wood of Ashdown Park. Ashdown park is a designated Site of Special Scientific Interest (SSSI).