Tarbolton Motte is a 12th century mutilated earthwork motte and bailey fortress, founded by Gilbert, son of Richer de Boyville. Standing on a prominent spur with steep natural slopes to the south and east, there are the shallow remains of an eastern encasing motte ditch. With a south-western entrance, scarps and low banks encase the east bailey but the west bailey has been encroached upon by houses. Now on common ground, a June bonfire was lit on the flat-topped mound in the 19th century. 3 miles north-west is Barnweill Castle and 10 miles south-west is Greenan Castle.