Orchardton Tower is the only round tower-house in Scotland. It was built in the mid 15th century for John Carnys (or Cairns). A door at ground level leads to a cellar with a vaulted roof. Access to the rest of the tower is via an external stair to the first floor. None of the upper floors remain, but there is a spiral staircase within the thickness of the wall that leads up to the parapet and is covered by a small gabled cap-house. There are also the remains of courtyard buildings.