Mapping Mountains – Significant Name Changes – 100m Twmpau

Coed Penllyn (SH 786 696) 

There has been a Significant Name Change to a hill that is listed in the 100m Twmpau, 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 Penllyn (SH 786 696)

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

100m Twmpau - Welsh hills at or above 100m and below 200m in height that have 30m minimum drop, with an accompanying sub list entitled the 100m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 100m and below 200m in height with 20m or more and below 30m of drop.  The list is authored by Myrddyn Phillips, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

100m Twmpau by Myrddyn Phillips

The hill is adjoined to the Mynydd Hiraethog group of hills, which are situated in the northern part of North Wales (Region A, Sub-Region A2), and it is positioned with the A470 road to its west and a minor road to its east, and has the town of Llanrwst towards the south. 

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

When the original 100m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill was included in the accompanying Hills to be surveyed sub list under the invented and transposed name of Pen Coed y Bortho, with an accompanying note stating; Name from wood to the West.

Pen Coed y Bortho

193m

SH786697

115

17

Height from 1989 1:50000 map. Name from wood to the West.

During my early hill listing I thought it appropriate to either invent a name for a hill, or use a name that appeared near to the summit of the hill on Ordnance Survey maps of the day, with little consideration for the meaning of the name and where it was appropriately applied to.  My preference was to use farm names and put Pen, Bryn or Moel in front of them or as in this instance transpose the name of a wood and add the word Pen to it.  This is not a practice that I now advocate as with time and inclination place-name data can be improved either by asking local people or by examining historic documents, through this form of research an appropriate name for the hill can usually be found.

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, and it is the series of Ordnance Survey Six-Inch maps coupled with the Ordnance Survey map that was hosted on the Geograph website that form the basis of the change in the listed name of this hill. 

Extract from the Ordnance Survey series of Six-Inch maps published in 1900

The Ordnance Survey series of Six-Inch maps formed the base map Ordnance Survey used for many decades leading to the production of the 1:10,000 Series of maps, both have now been superseded by the digitised Master Map.  The series of Six-Inch maps are excellent for name placement and especially so compared to the contemporary Ordnance Survey 1:25,000 Explorer map, and it is the series of Six-Inch maps that name the plantation where the summit of this hill is situated as firstly Planhigfa Penllyn in the 1900 publication and later as Penllyn Wood in the 1953 publication.

Extract from the Ordnance Survey series of Six-Inch maps published in 1953

However, it is the Ordnance Survey Vector Map Local that was hosted on the Geograph website and which was entitled the Interactive Coverage Map that uses the full Welsh term for this wood and names it as Coed Penllyn.

Therefore, the name this hill is now listed by in the 100m Twmpau is Coed Penllyn, and this was derived from the foundations of the name appearing on the Ordnance Survey series of Six-Inch maps and lastly with the name appearing in its full Welsh form on the Ordnance Survey Vector Map Local that was hosted on the Geograph website and which was entitled the Interactive Coverage Map. 

 

The full details for the hill are:

Group:  Mynydd Hiraethog

Name:  Coed Penllyn

Previously Listed Name:  Pen Coed y Bortho 

OS 1:50,000 map:  115

Summit Height:  198.0m (LIDAR) 

Summit Grid Reference:  SH 78630 69665 (LIDAR) 

Bwlch Height:  170.9m (LIDAR) 

Bwlch Grid Reference:  SH 78892 70134 (LIDAR) 

Drop:  27.1m (LIDAR) 

 

Myrddyn Phillips (June 2026) 

Mapping Mountains – Hill Reclassifications – The Fours – The 400m Hills of England

 

Pt. 426.6m (SO 404 953) – Sub-Four exclusion

There has been an exclusion from the listing of the 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. 

Pt. 426.6m (SO 404 953)

The criteria for the list that this exclusion 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 being listed by the point (426.6m) notation and it is adjoined to the Stiperstones group of hills, which are situated adoined to the Welsh border, and it is positioned encircled by minor roads, with the A489 road farther to its south and the A49 road farther to its east, and has the town of Church Stretton towards the east south-east.

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 listed with an estimated c 15m of drop, based on the 428m summit spot height that appears on the Ordnance Survey 1:25,000 Explorer map and an estimated c 413m col height, based on interpolation of 5m contouring between 410m – 415m. 

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.

Therefore, the exclusion of this hill from Sub-Four status is due to LIDAR analysis, resulting in a 426.6m summit height and a 412.2m col height, with these values giving this hill 14.4m of drop, which is insufficient for it to be classified as a Sub-Four. 

 

The full details for the hill are:

Group:  Stiperstones

Name:  Pt. 426.6m

OS 1:50,000 map:  137

Summit Height:  426.6m (LIDAR)

Summit Grid Reference:  SO 40462 95367 (LIDAR)

Col Height:  412.2m (LIDAR)

Col Grid Reference:  SO 40807 95232 (LIDAR)

Drop:  14.4m (LIDAR)

 

For the additions, deletions and reclassifications to The Fours – The 400m Hills of England reported on Mapping Mountains since the December 2013 publication of the 1^st edition of this list by Europeaklist please consult the following Change Registers:

 

The Fours

 

Sub-Fours

 

Myrddyn Phillips and Aled Williams (June 2026)              

 

Mapping Mountains – Significant Name Changes – 30-99m Twmpau

Gwales (SM 598 094 & SM 598 093) 

There has been a Significant Name Change that is retrospective to a hill that is listed in the 30-99m Twmpau, with the summit height and its location, the drop and status of the hill derived from detail on maps produced from Ordnance Survey data.                       

Gwales (SM 598 094 & SM 598 093)

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

30-99m Twmpau - Welsh hills at or above 30m and below 100m in height that have 30m minimum drop, with an accompanying sub list entitled the 30-99m Sub-Twmpau, with the criteria for this sub category being all Welsh hills at or above 30m and below 100m in height with 20m or more and below 30m of drop.  The list is authored by Myrddyn Phillips, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

30-99m Twmpau by Myrddyn Phillips

The hill is adjoined to the Garn Fawr group of hills, which are situated in the south-western part of South Wales (Region B, Sub-Region B1), and it is positioned with the nearest minor road on the mainland to its east, and has the town of Hwlffordd (Haverfordwest) on the mainland towards the east north-east. 

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

When the original 30-99m height band of Welsh P30 hills were published on Geoff Crowder’s v-g.me website, this hill appeared under the transposed name of Grassholm Island, which is a prominent name that appears adjacent to this island on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map.

Grassholm Island

42m

SM598093

157

36

During my early hill listing I thought it appropriate to either invent a name for a hill or use a name that appeared near to the summit of the hill on Ordnance Survey maps of the day, with little consideration for the meaning of the name or the language used and where the name was appropriately applied to.  This is not a practice that I now advocate as with time and inclination place-name data can be improved either by asking local people or by examining historic documents, through this form of research an appropriate name for the hill can usually be found.

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 30-99m Twmpau is Gwales, and this was derived from various sources including the Dictionary of the Place-Names of Wales by Hywel Wyn Owen and Richard Morgan and published by Gomer Press. 

 

The full details for the hill are:

Group:  Garn Fawr

Name:  Gwales 

Previously Listed Name:  Grassholm Island   

OS 1:50,000 map:  157

Summit Height:  42m (spot height) 

Summit Grid Reference:  SM 59840 09415 & SM 59825 09366 (spot height)               

Bwlch Height:  N/A (sea level) 

Bwlch Grid Reference:  N/A (sea level) 

Drop:  42m (spot height) 

 

Myrddyn Phillips (June 2026)

 

  

Monthly Synopsis

 

Synopsis of all major changes detailed on Mapping Mountains during the last calendar month.  These can include new, confirmation and retrospective changes

 

Hill Reclassifications: 

Llethr Gwaered (SN 795 626) - Pellennig addition

Shadwell Hill (SO 201 865) - Sub-Four addition

Rhos Ffidl (SO 206 854) - Sub-Four addition

 

Significant Height Revisions: 

Craig Ysgafn (SH 659 443) - 600m Twmpau and The Welsh Highlands - Uchafion Cymru

Craig Ysgafn (SH 660 442) - The Welsh Highlands - Uchafion Cymru

Cefn y Coed (SO 211 934) - Y Trichant - The 300m Hills of Wales and Y Trechol - The Dominant Hills of Wales

Summit Relocations: 

Cae Tros Ffordd (SH 797 643) - The Welsh P15s

Foel Fawr (SH 728 392) - The Deweys

Significant Name Changes: 

Tai Isa (SH 780 620) - The Welsh P15s

Cae Tros Ffordd (SH 797 643) - The Welsh P15s

Mapping Mountains – Significant Name Changes – The Welsh P15s

 

Cae Tros Ffordd (SH 797 643) 

There has been a Significant Name Change to a hill that is listed in 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 Cae Tros Ffordd (SH 797 643)

The criteria for the list that this name change 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 hill is adjoined to the Mynydd Hiraethog group of hills, which are situated in the northern part of North Wales (Region A, Sub-Region A2), and it is positioned encircled by minor roads with the A470 road farther to its west, and has the town of Llanrwst towards the south.

When the listing that became known as The Welsh P15s was being compiled, this hill was listed under the point (Pt. 129m) notation, with an estimated c 20m of drop, based on the 129m summit spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map and an estimated c 109m bwlch height, based on interpolation of 10m contouring between 100m – 110m. 

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

As the summit of this hill comprises bounded land the details for it were examined on the Tithe map.  The term Tithe map is generally given to a map of a Welsh or English parish or township and which was prepared after the 1836 Tithe Commutation Act.  This act allowed tithes to be paid in cash rather than goods.  The Tithe maps gave names of owners and occupiers of land in each parish and importantly for place-name research they also included the name of enclosed land.  This enclosed land is usually based on a field system, however not every field is given a name, but many are and especially so in Wales. 

Extract from the Tithe map

The enclosed land where the summit of this hill is situated is given the number 843 on the Tithe map, this can be cross referenced against the apportionments; it is these apportionments that give the name of the owner or occupier of the land as well as the name of the land.  The land where the summit of this hill is situated is named Cae Tros Ffordd in the apportionments, with the details on the Tithe map appearing in the parish named as Eglwys-fach and in the county named as Caernarfon. 

Extract from the apportionments

Therefore, the name this hill is now listed by in the The Welsh P15s is Cae Tros Ffordd, and this was derived from the Tithe map. 

 

The full details for the hill are: 

Group:  Mynydd Hiraethog 

Name:  Cae Tros Ffordd 

Previously Listed Name:  Pt. 129m 

OS 1:50,000 map:  115

Summit Height:  127.1m (LIDAR)                                                           

Summit Grid Reference:  SH 79756 64305 (LIDAR) 

Bwlch Height:  107.9m (LIDAR) 

Bwlch Grid Reference:  SH 79900 64455 (LIDAR) 

Drop:  19.2m (LIDAR) 

 

Myrddyn Phillips (May 2026)