Downhill House was a mansion built in the late 18th century for Frederick, 4th Earl of Bristol and Lord Bishop of Derry(popularly known as 'the Earl-Bishop'), at Downhill, County Londonderry. Much of the building was destroyed by fire in 1851 before being rebuilt in the 1870s. It fell into disrepair after the Second World War.
 
Downhill House is now part of The National Trust property of Downhill Demesne and Mussenden Temple.