Clipyn Du is a mountain in northern Powys in Wales.

Also known as Tarren Bwlch-Gwyn or Siambwr Trawsfynydd, 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 582 m (1,909 ft) and a topographic prominence of 124 m (407 ft), so is classed as a HuMP, having over 100 metres of prominence.

Tarren Bwlch-Gwyn is the name of a steep-sided escarpment nearby.

This Powys location article is a stub.