Mapping Mountains – Significant Name Changes – The Fours – The 400m Hills of England

Disgwylfa (SO 172 841)

There has been a Significant Name Change to a hill that is listed in The Fours – The 400m Hills of England, with the summit height, col height and their locations, the drop and status of the hill derived from LIDAR analysis conducted by Myrddyn Phillips. 

LIDAR image of Disgwylfa (SO 172 841)

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

The Fours – The 400m Hills of England - English hills at or above 400m and below 500m in height that have 30m minimum drop, accompanying the main list is a sub list entitled the Sub-Fours, the criteria for which are all English hills at or above 400m and below 500m in height that have 15m or more and below 30m of drop.  The list is co-authored by Myrddyn Phillips and Aled Williams and is available to download in Google Doc format from the Mapping Mountains site.

The Fours - The 400m Hills of England by Myrddyn Phillips and Aled Williams

The hill is adjoined to the Cilfaesty group of hills, which are situated adjoined to the Welsh border, and it is positioned with the B4368 road to its north, and minor roads to its west and east, and has the town of Ceri towards the north north-west.

When the Introduction to the first group of hills for the updated and revised listing of the The Fours – The 400m Hills of England was published by Mapping Mountains on the 10^th September 2022, it was announced that the accompanying sub lists were being revised with the two 390m categories dispensed with and the criteria and name of the 400m Sub-Fours revised.  The one accompanying sub list is now named the Sub-Fours with its criteria being all English hills 400m and above and below 500m in height that have 15m and more and below 30m of drop.

Prior to this revision this hill was provisionally listed under the name of Bettws Hill Wood, which is a prominent name that appears near its summit on the Ordnance Survey 1:25,000 Explorer map, with an estimated c 15m of drop, based on the 427m summit spot height positioned at SO 17503 84053 that appears on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map and an estimated c 412m col height, based on interpolation of 10m contouring between 410m – 420m. 

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

Since the original compilation of this list 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 latter map that has prompted the change in the listed name of this hill.

The One-Inch ‘Old Series’ map was the first map that Ordnance Survey produced, and their publication culminated from the whole of Britain being surveyed between 1791 and 1874 and the detail gathered therein produced at a scale of one inch to the mile and published in sheet format between 1805 and 1874.  The One-Inch ‘Old Series’ maps for the whole of Wales are now available online; they are also available in map format as enlarged and re-projected versions to match the scale and dimensions of the Ordnance Survey 1:50,000 Landranger series and are published by Cassini.  This series of maps form another important part in the study of upland place-names and bridge the timeframe leading up to the production of the Ordnance Survey base map of the Six-Inch series, and importantly for this hill and its listed name, it is this map that places the name Disgwylfa adjacent to the summit of this hill. 

Extract from the Ordnance Survey One-Inch 'Old Series' map

Therefore, the name this hill is now listed by in The Fours – The 400m Hills of England is Disgwylfa, and this was derived from the Ordnance Survey One-Inch ‘Old Series’ map. 

 

The full details for the hill are:

Group:  Cilfaesty

Name:  Disgwylfa

Previously Listed Name:  Bettws Hill Wood

OS 1:50,000 map:  136

Summit Height:  428.9m (LIDAR)

Summit Grid Reference:  SO 17246 84195 (LIDAR)

Col Height:  410.9m (LIDAR)

Col Grid Reference:  SO 17775 83941 (LIDAR)

Drop:  18.0m (LIDAR)

 

Myrddyn Phillips and Aled Williams (March 2026)