Llyn y Fan Fach Llyn y Fan Fach Llyn y Fan Fach (Welsh meaning "Lake of the small hill") is a lake of approximately 10 hectares on the northern margin of the Black Mountain in Carmarthenshire, South Wales and lying within the Brecon Beacons National Park. The lake lies at an altitude of approximately , immediately to the north of the ridge of the Carmarthen Fans. It is the smaller of two lakes within this mountain massif: the slightly larger Llyn y Fan Fawr is about to the east. The lake is overlooked by several prominent mountain peaks, especially Picws Du and Waun Lefrith.
Pen y Fan held the ashes or other remnants of a dead person or persons since multiple burials together are common in the British Bronze Age. It also held grave goods left with the human remains, such as flint tools, cinerary urns, or flower tributes. The similar round barrow on Fan Foel was excavated in 2002-4 and revealed such items in the central cist, the flowers being those of meadowsweet. The name "Pen y Fan" consists of the Welsh words "pen" ('top, head, peak, summit', etc.), "y" ('the') and "fan", a mutated form of "ban" ('summit, crest, peak, beacon, hill, mountain', etc.). The