Pen y Gadair Fawr
One classification here — Simm — belongs to a list OpenFell holds only part of, so it has no list page. See how far the coverage goes.

- Height
- 800 m · 2,625 ft
- Prominence
- 47 m
- Grid reference
- SO 22946 28763
- Coordinates
- 51.95196, -3.12264
- County / area
- Powys
- Region
- Llandovery to Monmouth
- OS Landranger
- 161
- OS Explorer
- OL13N
- Summit feature
- cairn
- Key col
- SO227291 (753 m)
About Pen y Gadair Fawr
Pen y Gadair Fawr is a subsidiary summit of Waun Fach and the second highest peak in the Black Mountains of south-eastern Wales. Marked by a medium-sized cairn, it is a far more shapely top than its parent 1.5 km to the north-west. Its own top, Pen Twyn Mawr at 658 metres, lies roughly 2 km to the south-east.
Background written from facts in the Wikipedia article on Pen y Gadair Fawr (CC BY-SA 4.0). Heights, prominence and grid references come from the Database of British & Irish Hills, not from Wikipedia.
Access rights here
Conditional Right to roam: Right to roam only on mapped CRoW open access land.
Permission needed Wild camping: Permission needed everywhere.
General position for Wales — local byelaws, seasonal restrictions and closures can override it. Full details: access rights in Wales · check another location.
Daylight at this summit today
- Sunrise
- —
- Sunset
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- Daylight
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- Civil twilight ends
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Computed astronomically for 51.952, -3.123. Plan your finish with the daylight safety planner.
Summit weather live
Loading forecast for the summit (800 m)…
Forecast adjusted to summit altitude. Weather data from MET Norway (CC BY 4.0).
Finding the summit
The recorded summit point is cairn. On broad or flat summits the obvious cairn is not always the true high point.
- Survey method
- obvious summit
- Record revised
- 28-Oct-01
- Drop measured from
- SO227291 · 753 m
Survey notes are field observations recorded in the Database of British & Irish Hills (v18.3, CC BY 4.0) by the hill-surveying community.
Which hill this one belongs to
Pen y Gadair Fawr is not counted as an independent hill in its own right. In prominence terms it belongs to Waun Fach (811 m) — the nearest Marilyn you can reach from this summit without first dropping below its key col, 753 m.
Grouping is by prominence alone: a summit belongs to the nearest higher Marilyn it connects to without a deeper intervening col. Over a large massif that can gather hills no one would walk in a single day, and which few would describe as parts of the same mountain — it is a measure of independence, not a suggested route.
Nearest listed peaks
| Peak | Height | Distance |
|---|---|---|
| Waun Fach | 811 m | 1.9 km |
| Mynydd Llysiau | 663 m | 2.4 km |
| Pen Twyn Mawr | 658 m | 2.4 km |
| Chwarel y Fan | 679 m | 2.9 km |
| Pen Twyn Glas | 646 m | 3.4 km |
| Rhos Dirion | 713.4 m | 4.9 km |