The area extends from the edge of the Black Mountain in the west eastwards to the A470 Brecon to Merthyr Tydfil road, just west of the Brecon Beacons themselves. It includes the peaks of Fan Fawr (734 m), Fan Frynych (629 m), Craig Cerrig-gleisiad (629 m), Fan Llia (632 m), Fan Nedd (663 m), Fan Gyhirych (725 m), Fan Bwlch Chwyth (603 m) and Cefn Cul (562 m). Traditionally Fforest Fawr also included the peaks of Fan Hir and Fan Brycheiniog, although the modern recreational use of the name tends to be restricted to the area east of the Black Mountain of which they form a part.