Drygarn Fawr is a Hewitt of 644 m in Powys. The key col lies 17.1 km away to the north, at 386.5 m.
Its closest neighbour in this register, Pen y Garn, is 19.8 km away. In the database's South-West Wales region it is the highest of two register hills, above Pen y Garn. It shares its height of 644 m with Coomnadiha. On the Hewitts height ladder it sits between Devilsmother (645 m) and Coomnadiha (644 m). Its nearest higher summit, Y Garn (684 m, 28.1 km north), is a listed top not profiled here. The summit is marked by a trig point.