Rhinog Fach is a mountain located in Snowdonia, North Wales, forming part of the Rhinogydd range in the county of Gwynedd. The summit reaches an elevation of 712 metres (2,336 ft) above sea level and has a topographic prominence of 151 metres (495 ft). Although technically a subsidiary summit of the higher peak Y Llethr, Rhinog Fach is classified as a Marilyn—a hill with a prominence of at least 150 metres—as well as a Hewitt, Nuttall, and a member of the Welsh mountain listing systems.
Geographically, the mountain lies at grid reference SH 664 270 on the Ordnance Survey Landranger map 124. It is situated south of its larger neighbour Rhinog Fawr, from which it is separated by the mountain pass Bwlch Drws Ardudwy. The terrain is noted for its rugged, rocky summit, contrasting with the more grassy summit of Y Llethr. The name “Rhinog Fach” derives from Welsh, where rhinog denotes a “prominent ridge” and fach means “small” or “little,” distinguishing it from the nearby Rhinog Fawr (“big Rhinog”).
Rhinog Fach is a popular destination for hillwalkers and mountaineers, offering challenging ascents and panoramic views of the surrounding Snowdonia landscape, including the coastline of the Welsh west. The mountain is also of interest to naturalists for its diverse flora and fauna typical of the highland environments of the Rhinogydd.