Glyn-dyrys lock is a double lock, no. 4 and 5, on the Glamorganshire Canal (nprn 34425). There are scanty remains, consisting mostly of the masonry core of the lock chambers; the by-pass inlet is visible and there is evidence visible of the centre gate housing and the west side of the tail bridge. Immediately adjacent and parallel on the west side is a covered dock. The lock-keeper's cottage (nprn 91554) stands to the northwest.
Site visited B.A.Malaws, RCAHMW, December 1978.