Carmarthenshire, the southeastern part of Dyfed, is mostly hilly, except for the river valleys and coastal strip. Fforest Fawr and Black Mountain extend into the east of Carmarthenshire and the Cambrian Mountains into the north. The highest point in Carmarthenshire is Fan Brycheiniog, , on the border with Powys. The River Towy is the largest river and drains into the Bristol Channel, as do the River Loughor, the River Gwendraeth and the River Taf. Carmarthenshire has a long coastline which is deeply cut by the estuaries of the Loughor, Gwendraeth, Tywi and Taf. The south coast has many fishing villages and sandy beaches and the eastern part around Llanelli and Burry Port is more industrial.