| Pen Twyn Mawr | |
|---|---|
 Pen y Gadair Fawr from the summit of Pen Twyn Mawr | |
| Highest point | |
| Elevation | 658 m (2,159 ft) |
| Prominence | 17 m (56 ft) |
| Parent peak | Pen y Gadair Fawr |
| Listing | Nuttall |
| Naming | |
| Language of name | Welsh |
| Geography | |
 | |
| Location | Black Mountains, South Wales |
| OS grid | SO241266 |
| Topo map | OS Landranger 161 |
Pen Twyn Mawr is a top of Pen y Gadair Fawr in the Black Mountains in south-eastern Wales. It lies on one of the many south ridges of Waun Fach.
The summit is marked by a pile of stones in an area of sandy soil and heather. Pen y Gadair Fawr is to the north, Chwarel y Fan to the east and Pen Allt-mawr to the west.[1]
- ^ Nuttall, John & Anne (1999). The Mountains of England & Wales - Volume 1: Wales (2nd edition ed.). Milnthorpe, Cumbria: Cicerone. ISBN 1-85284-304-7.