Mapping Mountains – Significant Name Changes – Y Trichant – The 300m Hills of Wales

Castell Cefnllys (SO 088 613) 

There has been a Significant Name Change to a hill that is listed in the Y Trichant – The 300m 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. 

LIDAR image of Castell Cefnllys (SO 088 613)

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

Y Trichant – The 300m Hills of Wales – Welsh hills at or above 300m and below 400m in height that have 30m minimum drop, with an accompanying sub list entitled the Sub-Trichant, with the criteria for this sub category being all Welsh hills at or above 300m and below 400m in height with 20m or more and below 30m of drop.  The list is authored by Myrddyn Phillips with the Introduction to the list and the renaming of it appearing on Mapping Mountains on the 13^th May 2017, and the Introduction to the Mapping Mountains publication of the list appearing on the 1^st January 2022. 

Y Trichant - The 300m Hills of Wales by Myrddyn Phillips

The hill is adjoined to the Hirddywel group of hills, which are situated in the northern part of South Wales (Region B, Sub-Region B2), and it is positioned with minor roads to its north north-east, west and south, and the A483 road farther to its west, and has the town of Llandrindod towards the west.

The hill appeared in the original 300m height band of Welsh P30 hills published on Geoff Crowder’s v-g.me website, under the transposed name of Cefnllys Castle, with an accompanying note stating; aka Castle Bank.  The former name appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map, whilst the latter appears on the Ordnance Survey 1:25,000 Explorer map.

Cefnllys Castle

304m

SO089614

147

200

Clem/Yeaman. aka Castle Bank

Since the original publication of the Welsh P30 lists on Geoff Crowder’s v-g.me website there have been a number of maps made available online.  Some of these are historic such as the series of Six-Inch maps on the National Library of Scotland website.  Whilst others were digitally updated such as the Ordnance Survey Vector Map Local that was hosted on the Geograph website and which was entitled the Interactive Coverage Map, whilst others are current and digitally updated such as the interactive mapping on the Magic Maps and WalkLakes websites.  Two of the historic maps now available online are the Ordnance Survey Draft Surveyors map which formed the basis for the first publicly available Ordnance Survey One-Inch ‘Old Series’ map, and it is the Ordnance Survey Draft Surveyors map that prompts the change in the listed name of this hill. 

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

The Draft Surveyors maps consist of the preliminary drawings made by the Ordnance Survey surveyors between the 1780s and 1840 and formed the basis for the first publicly available One-Inch map.  They were drawn at scales of six inches to the mile for areas considered of particular military significance and down to two inches to the mile for other areas.  Fair copies were then produced from these preliminary drawings to one inch to the mile and then copper plates were prepared for printing.  The Draft Surveyors maps for the whole of Wales are now available online and they form an important part in the study of Welsh upland place-names as they bridge the time frame between the late 18^th century and the mid-19^th century when the Ordnance Survey produced their first One-Inch maps, and importantly for this hill and its listed name, it is this map that uses the form of Cefnllys Castell adjacent to the summit of this hill. 

Extract from the Ordnance Survey Draft Surveyors Map

The intricacies of language and prioritising one in favour of another for listing a hill is fraught with complication, with originating Cymraeg names being anglicised and also originating English names being cymricised, examples such as these are more common in border country and especially so for anglicised forms.  There is no steadfast rule that fits all, but as a standard a name that has its origins in the Welsh language and where this is substantiated by either historic documentation and/or contemporary usage should be prioritised in favour of a contemporary anglicised or English version of the name.  Likewise, if a name exists where an element of it is in English and if this name applies to a hill that is situated in a Welsh speaking part of Wales it is standard practice to use a full Welsh term for the name.  It is also standard practice to use a Welsh name for a hill if another name exists that has originated in a different language.

Therefore, the name this hill is now listed by in the Y Trichant – The 300m Hills of Wales is Castell Cefnllys and this was derived from the Ordnance Survey Draft Surveyors Map, with the language protocol also being used. 

 

The full details for the hill are: 

Group:  Hirddywel 

Name:  Castell Cefnllys 

Previously Listed Name:  Cefnllys Castle 

OS 1:50,000 map:  147

Summit Height:  310.45m (LIDAR)                                                           

Summit Grid Reference:  SO 08841 61344 (LIDAR) 

Bwlch Height:  233.3m (LIDAR) 

Bwlch Grid Reference:  SO 10270 62837 (LIDAR) 

Drop:  77.1m (LIDAR) 

 

My thanks to Aled Williams for advice relating to the listed name of this hill

Myrddyn Phillips (April 2025)