Cwmystwyth mines are located in Cwmystwyth, Ceredigion, Wales and exploited a part of the Central Wales Orefield.
Cwm Ystwyth is a scheduled monument, with mining activity dating back to the Bronze Age. Silver, lead, and zinc mining peaked in the 18th century, and water was extensively used in the extraction process. The Banc Ty'nddôl, the earliest gold artifact discovered in Wales, was found on the site in 2002. Mining in the area caused substantial environmental impact; lead concentrations in the River Ystwyth declined from 0.4 mg/L in 1919 to below 0.05 mg/L in 1939, with fish populations returning to most of the river by 1975.