Cwmrhys slate quarry is located on enclosed land just outside Lampeter, to the north-east of the town. A hillside working, it is shown in operation on the Ordnance Survey first-edition map of 1889. In 1898 the quarry employed three men. It was seemingly still functioning at the time of the fourth edition map of 1938. When it finally closed is not recorded.
Sources:
OS County Series 25-inch map: sheet Cardiganshire XXXIV.13, editions of 1889 & 1905; County Series six-inch map, edition of 1938.

David Leighton, RCAHMW, 21 May 2015