Kilnsike Tower is a 16th century stone rectangular two storey defensible farmhouse. The bastle is constructed of massive masonry, laid in clay mortar and its south-east wall stands to the height of the original first floor entrance, with the gables a little higher. The north-west wall has been completely demolished and there are no narrow slit lights visible in any of the remaining walls. Half of the basement, is now below ground level and on the inside of the north-west gable at first floor level, are four small fitted compartments and a larger fitted cupboard. In the centre of the north-east gable is the entrance to the byre and both of the doorways are built from very large chamfered stone blocks, with squared stone lintels. The strong walls, with a removable stair up to the living quarters and a ground floor for stores and their livestock, provided a shelter from cross-border reivers, until help arrived. 3 miles south is Dykeraw Tower and 4 miles north-west is Fulton Tower.