Rhinog Fach is a Hewitt of 711.6 m in Gwynedd. Its drop clears the 150 m Marilyn standard by only 1 m.
Of the 31 register hills in Gwynedd, it has the smallest drop. It shares its height of 711.6 m with Tinto. On the Hewitts height ladder it sits between Corranabinnia (712 m) and Branstree (711.5 m).