Repentance Tower is a mid 16th century stone three storey tower house, founded by Sir John Maxwell of Terregles. Standing on Trailtrow Hill, the square fortified watchtower was built to warn Hoddom Castle by lighting a beacon on the ground, if an English raiding party crossed the border. The entrance is at first floor level and only small windows, gunloops and shot-holes give light, crowned by an encasing wall-walk and plain parapet, the roof was rebuilt with a stone fire beacon in the late 19th century. Near the site of Trailtrow Chapel, the word 'Repentance' carved over the lintel maybe in connected with its demolition. 6 miles south-west is Comlongon Castle.