Troed-yr-harn Motte is probably a small medieval earthwork motte, with the position of any bailey being lost. In marshy ground at the bottom of a valley full of streams, this ambiguous site is possibly a 13th century siege work, to the castles of Alexanderstone or Brecon. The low circular flat-topped mound, encased by the remains of a silted up ditch and a slight counterscarp bank, stands adjacent to the Slwch brook. 7 miles north-east is Talgarth Tower.