Foel Fraith is a hill in the Black Mountain in the county of Carmarthenshire, southwest Wales. It lies within the Brecon Beacons National Park and Fforest Fawr Geopark. Its plateau-like summit attains a height of above sea level. To the north the subsidiary summit of Cefn y Cylchau reaches , and to the southeast is the subsidiary summit of Carn Fadog or Cefn Carn Fadog, which reaches a height of .