Clipyn Du is a mountain in northern Powys in Wales. It is one of the higher summits of the area and is located a few miles north of Plynlimon (Pumlumon). It has an elevation of and a topographic prominence of , so is classed as a HuMP, having over 100 metres of prominence. Tarren Bwlch-Gwyn is the name of a steep-sided escarpment. Nearby is a lake, Glaslyn.
A natural cleft in the rick here is known as Siambwr Trawsfynydd. Owain Glyndà µr is thought to have camped here in 1401, prior to the Battle of Mynydd Hyddgen.