Dirlot Castle was built in the first half of the fourteenth century by Sir Reginald Cheyne. Although most castles in Caithness are on the coast, Dirlot Castle is about 20 miles inland. The castle was built on a plug of rock which rises to almost 15 metres in the River Thurso. The rock is adjacent to a bend in the river next to a deep pool, rumoured to hold treasure guarded by a vicious water horse. It was a small keep, probably more for a small garrison of soldiers than for great defensive purposes. The tower rose to about 18 metres and had three storeys. During its useful life it was occupied by the Cheynes, the Gunns, the Mackays and the Sutherlands, before it was abandoned around 1660. Stones from the building were used in other projects in the area including the wall of the nearby graveyard.