Mapping Mountains – Significant Name Changes – 200m Twmpau

Grogwynion (SN 720 725) 

There has been a Significant Name Change to a hill that is listed in the 200m Twmpau, with the summit height, bwlch height and their locations, the drop and status of the hill derived from LIDAR analysis and a subsequent Trimble GeoXH 6000 survey conducted by Myrddyn Phillips. 

Grogwynion (SN 720 725)

The criteria for the list that this name change applies to are: 

200m Twmpau - Welsh hills at or above 200m and below 300m in height with 30m minimum drop, with an accompanying sub list entitled the 200m Sub-Twmpau with the criteria for this sub category being all Welsh hills at or above 200m and below 300m in height with 20m or more and below 30m of drop, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

The 200m Twmpau by Myrddyn Phillips

The hill is adjoined to the Elenydd group of hills, which are situated in the central part of the Mid and West Wales Region (Region B, Sub-Region B2), and is positioned with minor roads to its north-east, north and south, and has the B4343 road to its east, and the village of Pont-rhyd-y-groes towards the east. 

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

When the original 200m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website this hill was listed under the name of Castell Graigwynion, which was a typo for Castell Grogwynion which is a prominent name that appears near the summit of this hill on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map.

Castell Graigwynion

289m

SN721724

135/147

213

Included by contour configuration

 

This was one of a number of hills visited during the day and I approached it from the north calling at the farm of Pengrogwynion, which is positioned directly under the hill to its north-east.  The front door was opened by Wendy Croket, I introduced myself and explained my interest in upland place-names and in particular the hill above the farm.  We talked at length and she told me about the ancient fortifications and after asking permission to visit, she kindly told me the best way up.  During the conversation she told me that the name of the hill is Grogwynion with the word Castell purely signifying the ancient hill fort as being the castle of the hill of Grogwynion.  We were soon joined by Caredig, who I then later met when descending from my last hill of the day. 

Caredig and Wendy

Therefore, the name this hill is now listed by in the 200m Twmpau is Grogwynion, and this was derived from local enquiry. 

 

The full details for the hill are:

Group:  Elenydd

Name:  Grogwynion

Previously Listed Name:  Castell Graigwynion   

OS 1:50,000 map:  135, 147

Summit Height:  288.6m (converted to OSGM15, Trimble GeoXH 6000) 

Summit Grid Reference:  SN 72068 72507 (Trimble GeoXH 6000) 

Bwlch Height:  255.8m (LIDAR) 

Bwlch Grid Reference:  SN 71921 72581 (LIDAR) 

Drop:  32.7m (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

Myrddyn Phillips (September 2021)