Kenfig Pool (Welsh: Pwll Cynffig) is a national nature reserve situated near Porthcawl, Bridgend. Wild storms and huge tides between the 13th and 15th centuries are mainly responsible for creating the Kenfig dunes near Porthcawl, as they threw vast quantities of sand up over the Glamorgan coast. This buried the nearby borough of Kenfig, and its castle, of which only the tower is still visible. At 70 acres the second largest (after Llangorse Lake) freshwater lake in south Wales. Kenfig Pool lies at the heart of the national nature reserve and is a valuable stopping point for migrating birds. The lake's maximum depth is about 12 feet.