Torthorwald Castle is a stone motte and bailey fortress, with a 14th century keep built on the motte. Both the basement and first floor hall of this oblong keep are vaulted and in one corner is a turnpike stair to access the upper floors. The earlier earthworks surrounding the ruined keep have considerable ramparts and wet ditches. 5 miles south-west is Dumfries Castle and 5 miles north-east is Lochmaben Castle.