Mapping Mountains - Hill Reclassifications - Y Pellennig - The Remotest Hills of Wales
Llethr Gwaered (SN 795 626) – Pellennig addition (13th reclassification)
There has been an addition to the listing of Y Pellennig – The Remotest Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips.
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| LIDAR image of Llethr Gwaered (SN 795 626) |
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| Y Pellennig - The Remotest Hills of Wales by Myrddyn Phillips and Aled Williams |
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| Extract from the Ordnance Survey 1:25,000 Explorer map |
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| Extract from the interactive mapping hosted on the WalkLakes website |
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| The two Llethr Gwaered Pellennig summits; SH 795 626 and SN 801 625 |
The full details for the hill are:
Group: Drygarn Fawr
Name: Llethr Gwaered
OS 1:50,000 map: 147
Summit Height: 489.5m (LIDAR)
Summit Grid Reference: SN 79564 62624 (LIDAR)
Bwlch Height: 468.3m (LIDAR)
Bwlch Grid Reference: SN 79609 63025 (LIDAR)
Drop: 21.2m (LIDAR)
Remoteness: 3.800km (LIDAR)
For the additions and deletions to Y Pellennig – The Remotest Hills of Wales reported on Mapping Mountains please consult the following Change Register:
Y Pellennig – The Remotest Hills of Wales
Aled Williams and Myrddyn Phillips (May 2026)
Mapping Mountains - Hill Reclassifications - Y Pellennig - The Remotest Hills of Wales
Pt. 526.8m (SN 745 611) – Pellennig deletion (12th reclassification)
There has been a deletion to the listing of Y Pellennig – The Remotest Hills of Wales, with the summit height, bwlch height and their locations, the drop and status of the hill derived from a Trimble GeoXH 6000 summit survey and LIDAR bwlch analysis conducted by Myrddyn Phillips and Aled Williams.
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| Pt. 526.8m (SN 745 611) |
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| Y Pellennig - The Remotest Hills of Wales by Myrddyn Phillips and Aled Williams |
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| Extract from the Ordnance Survey 1:25,000 Explorer map |
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| Extract from the interactive mapping that was hosted on the OS Maps website |
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| The Trimble GeoXH 6000 gathering data at the summit of Pt. 526.8m (SN 745 611) |
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| LIDAR image of Pt. 526.8m (SN 745 611) |
The full details for the hill are:
Group: Esgair Wen
Name: Pt. 526.8m
OS 1:50,000 map: 146, 147
Summit Height: 526.8m (Trimble GeoXH 6000)
Summit Grid Reference: SN 74595 61119 (Trimble GeoXH 6000)
Bwlch Height: 512.0m (LIDAR)
Bwlch Grid Reference: SN 74980 61422 (LIDAR)
Drop: 14.8m (Trimble GeoXH 6000 summit and LIDAR bwlch)
Remoteness: 2.700km (no longer applicable)
For the additions and deletions to Y Pellennig – The Remotest Hills of Wales reported on Mapping Mountains please consult the following Change Register:
Y Pellennig – The Remotest Hills of Wales
Twll y Gwyddel (SM 705 225) – Pellennig addition (11th reclassification)
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| Twll y Gwyddel (SM 705 225) |
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| Extract from the Ordnance Survey 1:25,000 Explorer map |
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| Extract from the Ordnance Survey Vector Map Local hosted on the Geograph website |
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| Extract from the OS Maps website |
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| LIDAR DSM image of the stack found in Twll y Gwyddel. 1m contour (black), 10m contour (red) and sea level (yellow). |
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Pt. 22.2m (SM 701 226) – Pellennig addition (10th reclassification)
Significant Height Revisions post for Pt. 22.2m
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| Pt. 22.2m (SM 701 226) |
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| Extract from the Ordnance Survey 1:25,000 Explorer map |
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| Extract from the Ordnance Survey Vector Map Local hosted on the Geograph website |
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| Extract from the OS Maps website |
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| LIDAR image of Pt. 22.2m; 1m contour (black), 10m contour (red) and sea level (yellow) |
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| Close up LIDAR image of Pt. 22.2m; 1m contour (black), 10m contour (red) and sea level (yellow) |
Mapping Mountains - Hill Reclassifications - Y Pellennig - The Remotest Hills of Wales
Whiteford Burrows (SS 448 964) – Pellennig addition (9th reclassification)
Significant Height Revisions post for Whiteford Burrows
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| LIDAR image of Whiteford Burrows |
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| Extract from the Ordnance Survey 1:50,000 Landranger map |
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| LIDAR summit image of Whiteford Burrows |
Mapping Mountains - Hill Reclassifications - Y Pellennig - The Remotest Hills of Wales
THIS HILL HAS SUBSEQUENTLY BEEN DELETED FROM PELLENNIG STATUS
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| Pt. 526.8m (SN 745 611) |
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| Extract from the Ordnance Survey 1:25,000 Explorer map |
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| Extract from OS Maps |
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| The Trimble GeoXH 6000 gathering data at the summit of Pt. 526.8m |
Mapping Mountains - Hill Reclassifications - Y Pellennig - The Remotest Hills of Wales
Tap Llwyd (SH 719 065) – Pellennig addition (7th reclassification)
Survey post for Tap Llwyd
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| Tap Llwyd (SH 719 065) |
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| The Trimble GeoXH 6000 gathering data at the summit of Tap Llwyd |
Myrddyn Phillips and Aled Williams (April 2018)
Mapping Mountains - Hill Reclassifications - Y Pellennig - The Remotest Hills of Wales
Pembrey Forest (SN 393 016) - Pellennig deletion (6th reclassification)
The bwlch position given above connects this hill to the Pembrey Forest Ski Slope, which is given a much larger 25m ring contour and also a 30m ring contour; although in all probability the summit has been altered during the building of the ski slope. The critical bwlch for whichever high point is taken is positioned at SN 409 019 and is c 7m high.
Mapping Mountains - Hill Reclassifications - Y Pellennig - The Remotest Hills of Wales
Esgair y Llyn (SN 841 701) - Pellennig addition (5th reclassification)
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| Esgair y Llyn (SN 841 701) |
The hill is situated in the Elenydd group of hills which are positioned in the central part of the Region of Mid and West Wales. This grouping of hills forms one of the wildest in Wales and takes in some of the most remote hills in the country. The hill is situated in an immense grassland of moor and tussocks with Llyn Cerrigllwydion Isaf to its south-east and the higher summits of Cnapyn Drawsffos (SN 834 706) to its north-west and Blaen Rhestr (SN 843 693) towards its south. Any towns or villages are a far distance away with Ysbyty Ystwyth towards the west and Rhaeadr Gwy (Rhayader) towards the east.
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| The Trimble GeoXH 6000 gathering data at the summit of Esgair y Llyn |
This now brings the overall total for Y Pellennig to 169 hills for the Complete list (All Wales), with the total for the Mainland Wales list being 125 hills. The Master List will be duly updated on the Mapping Mountains site.
Bryn Llwyd (SN 835 920) - Pellennig addition (4th reclassification)
1st Survey post and 2nd survey post for Bryn Llwyd
Significant Name Changes post for Bryn Llwyd
There has been a new hill that has entered the list of Y Pellennig – The Remotest Hills of Wales, due to a recent Trimble survey. The hill is situated in the Pumlumon group of hills in the northern part of mid Wales and is situated between the towns of Llanidloes to its south-east and Machynlleth to its north-west.
| Bryn Llwyd (SN 835 920) now confirmed as a Pellennig hill |
Mapping Mountains - Hill Reclassifications - Y Pellennig - The Remotest Hills of Wales
Graig Fach (SN 821 930) - Pellennig deletion (3rd reclassification)
1st Survey post for Graig Fach
2nd Survey post for Graig Fach
There has been a deletion of a hill from the list of Y Pellennig – The Remotest Hills of Wales, due to a survey with the Trimble GeoXH 6000. The hill is situated in the Pumlumon group in northern mid Wales and is situated between the towns of Machynlleth to its north-west and Llanidloes to its south-east with the mountain lakes of Glaslyn to its north and Bugeilyn to its south.
Graig Fach has a 514m summit spot height and bwlch contouring between 490m – 500m with a 499m spot height appearing on the Ordnance Survey enlarged mapping on the Geograph website, this latter spot height is positioned on the track and interpolation suggests that it is not positioned where the critical bwlch is situated.
This now brings the overall total for Y Pellennig to 167 hills for the Complete list (All Wales), with the total for the Mainland Wales list also decreasing by one to 123 hills. The Master List will be duly updated on the Mapping Mountains site.
| Graig Fach (SN 821 930) now deleted from the Y Pellennig list |
Mapping Mountains - Hill Reclassifications - Y Pellennig - The Remotest Hills of Wales
Ynys Arw (SH 266 945) - Pellennig addition (2nd reclassification)
Survey post for Ynys Arw
Significant Height Revisions post for Ynys Arw
There has been a new hill that has entered the list of Y Pellennig – The Remotest Hills of Wales, due to a recent Trimble survey. The hill is situated on Ynysoedd y Moelrhoniaid, this small group of islands are positioned to the north-west, off the north-west coast of Ynys Môn; its name is Ynys Arw.
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| Ynys Arw (SH 266 945) - the new Pellennig hill |
Mapping Mountains - Hill Reclassifications - Y Pellennig - The Remotest Hills of Wales
Pen Diban (SH 112 205) - Pellennig reinstatement (1st reclassification)
Survey post for Pen Diban
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| Pen Diban (SH 112 205) |
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| Y Pellennig - The Remotest Hills of Wales by Myrddyn Phillips and Aled Williams |
The details for this hill were re-assessed when the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map became available online. This mapping had many spot heights not on other publicly available Ordnance Survey maps and for this hill it had 5m contouring which enabled a better assessment for the interpolated bwlch height, and with contouring at the bwlch between 5m - 10m, a c 6m bwlch height was estimated, resulting in this hill being listed with an estimated c 14m of drop and its deletion from Pellennig status.
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| The Trimble GeoXH 6000 gathering data at the summit of Pen Diban (SH 112 205) |
However, it was not until LIDAR became available that the bwlch details for this hill could be accurately re-assessed. The LIDAR (Light Detection & Ranging) technique produced highly accurate height data that is now freely available for much of England and Wales.
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| LIDAR image of Pen Diban (SH 112 205) |
Therefore, the reinstatement of this hill to Pellenig status is due to a Trimble GeoXH 6000 summit survey and LIDAR bwlch analysis, resulting in a 20.0m summit height and a 5.0m bwlch height, with these values giving this hill 15.0m of drop, which is sufficient for it to be classified as a Pellennig.
The full details for the hill are:
Group: Yr Eifl
Name: Pen Diban
OS 1:50,000 map: 123
Summit Height: 20.0m (Trimble GeoXH 6000)
Summit Grid Reference: SH 11235 20585 (Trimble GeoXH 6000)
Bwlch Height: 5.0m (LIDAR)
Bwlch Grid Reference: SH 11274 20954 (LIDAR)
Drop: 15.0m (Trimble GeoXH 6000 summit and LIDAR bwlch)
Remoteness: 5.710km
For the additions and deletions to Y Pellennig – The Remotest Hills of Wales reported on Mapping Mountains please consult the following Change Register:

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