Penhallam is the site of a medieval manor house surrounded by a protective moat.
The site is situated in the civil parish of Jacobstow in northeast Cornwall, United Kingdom, at OS Grid Ref SX224974 one mile west of Week St Mary and seven miles south of Bude.
The site is a grass-covered ruin showing the complete ground-plan of the manor. The manor dates from the late 12th century and was abandoned during the mid-14th century. Penhallam is one of only four such moated medieval manor sites in Cornwall and it consists of a quadrangle of buildings around a central courtyard.
The site of Penhallam is managed by English Heritage. In 1999 there was some controversy regarding this site and others in Cornwall under the care of English Heritage. Members of a pressure group, the Revived Cornish Stannary Parliament, removed several signs bearing the English Heritage name.