Mapping Mountains – Summit Relocations – The Welsh P15s

Coed Cefn Coch (SH 670 000) 

There has been a Summit Relocation to a hill that is listed in the The Welsh P15s, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Coed Cefn Coch (SH 670 000)

The criteria for the list that this summit relocation applies to are:

The Welsh P15s – Welsh hills with 15m minimum drop, irrespective of their height, with an accompanying sub list entitled the Welsh Sub-P15s, with the criteria for this sub category being all Welsh hills with 14m or more and below 15m of drop.  The list is authored by Myrddyn Phillips, with the Introduction to the list appearing on Mapping Mountains on the 10^th May 2019. 

The Welsh P15s by Myrddyn Phillips

The name the hill is listed by is Coed Cefn Coch, and it is adjoined to the Tarren y Gesail group of hills, which are situated in the south-western part of North Wales (Region A, Sub-Region A3), and it is positioned with a minor road to its south and the A493 road farther to its south-east, and has the small community of Cwrt towards the east.

When the original 100m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was not included in the accompanying Hills to be surveyed sub list, as it was considered not to meet the criteria then used for this sub category.

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-assessed and it was listed with an estimated c 20m of drop, based on an estimated c 186m summit height positioned at SH 67033 00055 and an estimated c 166m bwlch height, with both heights based on interpolation of 10m contouring. 

Extract from the Ordnance Survey 1:25,000 Explorer map

However, it was not until LIDAR became available that the 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. 

LIDAR summit image of Coed Cefn Coch (SH 670 000)

LIDAR analysis gives the highest ground on this hill as 185.55m positioned at SH 67096 00076.  This position is in a different field to where the previous interpolated summit was given, and this comes within the parameters of the Summit Relocations used within this page heading, these parameters are:

The term Summit Relocations applies when the high point of the hill is found to be positioned; in a different field, to a different feature such as in a conifer plantation,  within a different map contour either on Ordnance Survey maps or interactive mapping, to a different point where a number of potential summit positions are within close proximity, when natural ground or the natural and intact summit of a hill is confirmed compared to a higher point such as a raised field boundary or covered reservoir that is considered a relatively recent man-made construct, or the listing of a new twin summit or de-twinning of a summit, or a relocation of approximately 100 metres or more in distance from either the position of a map spot height or from where the summit of the hill was previously thought to exist.

Therefore, the summit height produced by LIDAR analysis is 185.55m and is positioned at SH 67096 00076, this position is not given a spot height on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and is approximately 63 metres north-eastward from where interpolation placed the previous summit position. 

 

The full details for the hill are: 

Group:  Tarren y Gesail 

Name:  Coed Cefn Coch 

OS 1:50,000 map:  135

Summit Height:  185.55m (LIDAR) 

Summit Grid Reference (New Position):  SH 67096 00076 (LIDAR) 

Bwlch Height:  166.5m (LIDAR) 

Bwlch Grid Reference:  SH 66830 00005 (LIDAR) 

Drop:  19.0m (LIDAR) 

 

Myrddyn Phillips (November 2025)