Mapping Mountains – Summit Relocations – Y Trichant – The 300m Hills of Wales

Cefn Uchaf (SN 958 800) 

There has been a Summit Relocation 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 Cefn Uchaf (SN 958 800)

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

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 name the hill is now listed by is Cefn Uchaf, and this was derived from the Tithe map, and it 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, west and south, with the A470 road farther to its north-west and the B4518 road farther to its east, and has the town of Llanidloes towards the north.

When the original 300m 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, as it was considered not to meet the criteria then used for the main P30 list.

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with 30m of drop, based on the 358m summit spot height positioned at SN 95816 80046 and the 328m bwlch spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map. 

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

However, it was not until a Trimble GeoXH 6000 survey and subsequent LIDAR analysis 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. 

Gathering data with the Trimble GeoXH 6000 on the summit area of Cefn Uchaf

There are a number of potential summit positions on this hill, with small outcrops of rock and other prominent undulations vying for the hill point.  Two positions were surveyed for summit position with the Trimble GeoXH 6000, with the highest coming to 357.4m positioned at SN 95873 80107, whilst LIDAR analysis gives the highest ground on this hill as 357.7m positioned at SN 95819 80021, and this position in relation to the spot height and also the highest Trimble GeoXH 6000 position 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 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. 

LIDAR summit image of Cefn Uchaf (SN 958 800)

Therefore, the summit height produced by LIDAR analysis is 357.7m and this is positioned at SN 95819 80021.  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 25 metres southward from where the 358m spot height appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map, and approximately 86 metres south-westward from where the highest of the two Trimble GeoXH 6000 surveys was conducted. 

 

The full details for the hill are: 

Group:  Hirddywel 

Name:  Cefn Uchaf 

OS 1:50,000 map:  136

Summit Height:  357.7m (LIDAR)                                                           

Summit Grid Reference (New Position):  SN 95819 80021 (LIDAR) 

Bwlch Height:  329.3m (LIDAR) 

Bwlch Grid Reference:  SN 95421 80193 (LIDAR) 

Drop:  28.4m (LIDAR) 

 

Myrddyn Phillips (September 2025) 

Mapping Mountains – Hill Reclassifications – Y Trichant – The 300m Hills of Wales

Cefn Uchaf (SN 958 800) – Trichant reclassified to Sub-Trichant

There has been confirmation of a reclassification 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. 

LIDA image of Cefn Uchaf (SN 958 800)

The criteria for the list that this reclassification 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 name the hill is now listed by is Cefn Uchaf, and this was derived from the Tithe map, and it 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, west and south, with the A470 road farther to its north-west and the B4518 road farther to its east, and has the town of Llanidloes towards the north.

When the original 300m 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, as it was considered not to meet the criteria then used for the main P30 list. 

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

After the sub list was standardised, and interpolated heights and drop values also included the details for this hill were re-evaluated and it was listed with 30m of drop, based on the 358m summit spot height and the 328m bwlch spot height that appeared on the Ordnance Survey Vector Map Local hosted on the Geograph website and which was entitled the Interactive Coverage Map.

However, it was not until a Trimble GeoXH 6000 survey and subsequent LIDAR analysis 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 confirmation of the reclassification of this hill to Sub-Trichant status is due to LIDAR analysis, resulting in a 357.7m summit height and a 329.3m bwlch height, with these values giving this hill 28.4m of drop, which is insufficient for it to be classified as a Trichant. 

 

The full details for the hill are: 

Group:  Hirddywel 

Name:  Cefn Uchaf 

OS 1:50,000 map:  136

Summit Height:  357.7m (LIDAR)                                                           

Summit Grid Reference:  SN 95819 80021 (LIDAR) 

Bwlch Height:  329.3m (LIDAR) 

Bwlch Grid Reference:  SN 95421 80193 (LIDAR) 

Drop:  28.4m (LIDAR) 

 

Myrddyn Phillips (September 2025) 

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

Cefn Uchaf (SN 958 800)

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. 

Cefn Uchaf (SN 958 800)

The criteria for the list that this name change affects 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 Hirthywel group of hills, which are situated in the north-eastern part of South Wales (Region B, Sub-Region B2), and it is positioned with a minor roads to its north, west and south, with the A470 road farther to its north-west and the B4518 road farther to its east, and has the town of Llanidloes towards the north.

The hill appeared in the original 300m height band of Welsh P30 hills published on Geoff Crowder’s v-g.me website, under the invented and transposed name of Bryn Nant Cae-garw, with an accompanying note stating; Name from stream to the South.

Bryn Nant Cae-garw

350c

SN959801

136

214

Two points of same height. Name from stream to the South

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 a name of a stream and put the word Bryn in front of 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.

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 84 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 Cefn Uchaf in the apportionments, with the details on the Tithe map appearing in the parish of Llangurig and in the county named as Montgomery.

Extract from the apportionments

Therefore, the name this hill is now listed by in the Y Trichant – The 300m Hills of Wales is Cefn Uchaf and this was derived from the Tithe map. 

 

The full details for the hill are: 

Group:  Hirddywel 

Name:  Cefn Uchaf 

Previously Listed Name:  Bryn Nant Cae-garw 

OS 1:50,000 map:  136

Summit Height:  357.7m (LIDAR)                                                           

Summit Grid Reference:  SN 95819 80021 (LIDAR) 

Bwlch Height:  329.3m (LIDAR) 

Bwlch Grid Reference:  SN 95421 80193 (LIDAR)

Drop:  28.4m (LIDAR)     

Myrddyn Phillips (July 2016)

Mapping Mountains – Trimble Surveys – Hirddywel

14.12.14  Bryn Mawr (SN 944 802) and Cefn Uchaf (SN 958 800)   

Cefn Uchaf (SH 958 800)

And what contrast two days can give, yesterday was dominated by an early morning chilled frost and radiant blue sky, whist today was a grey soggy affair with wind and rain, all good fun though.

Mark wanted to bag another Hump and Pedwar to take his yearly totals to a satisfactory point and suggested combining both targets by visiting one hill; Bryn Mawr.  Its summit also needed Trimbling as it has two points of equal map height.  Mark had also spotted that its neighbouring hill which the land where the summit is situated is named Cefn Uchaf on the Tithe map, is listed as a marginal Tump that is currently a Sub-P30 in the listings I have compiled.

We were away from Welshpool by 8.45am and with only a slight dusting of moistness in the air I hoped that the forecast of rain would keep at bay until after our walk had finished; no such luck.

As we approached the outskirts of Llanidloes the wiper blades on the car were heralding a wet morning.  Mark navigated us to the area of the bwlch between the two hills, we parked above the bwlch on a corner of the narrow lane as a track headed toward our first hill of the day; Bryn Mawr.

As we set off up the track the rain skimmed across the landscape with valleys of grey below and fields of green being blown by the wind, I only had time to take a couple of photos on our way up; all were with my back to the rain trying in vain to shield the camera from the wet stuff.

Heading into the soggy stuff on the way to the top of Bryn Mawr

I’d made a note of the ten figure grid references for the two tops of this hill; both are given the map height of 405m, one appearing on the enlarged Geograph map.  By the time we reached the high point of one of them I decided it was too wet to try and find the piece of paper with the grid references on it and just plonked the Trimble down on one of the high points, set it to ‘Log’ and stood with my back to the rain and wind.

First candidate for the high point of Bryn Mawr

Just to the north and over two fences was the second high point.  However, upon closer inspection this second point has two points that vied for being the highest, thankfully as the Trimble gathered data from its second and third placements the rain ceased for a few minutes and even the temptation of lightening skies teased us, not for long though as the rain soon started again.

Second candidate for the high point of Bryn Mawr

Third candidate for the high point of Bryn Mawr

We retraced our inward route, over the two fences and down the track and past the car onto the narrow lane, this took us straight over the area of the critical bwlch for our next hill.  We had a quick look at the land as we crossed the bwlch and proceeded up another track to the summit of the second hill.

The area of the critical bwlch of Cefn Uchaf

Once at the top we were confronted by about five possibilities for the highest point, as I set the Trimble to ‘Log’ on the first we arrived at, Mark ventured into the rain to assess some of the other candidates, as the five minutes of data collection neared its end I looked over at Mark on one of the other high point contenders and he was pointing toward me, signifying that the point he was on was lower than where I was.  However, a little further east from the first high point we had reached was another high point, I walked over and stood on its top and it looked as if it was higher than other contenders, Mark thought likewise when he joined me.  However, there were at least two other points of similar height.

First candidate for the high point of Cefn Uchaf came to 357.4m (357.370m converted to OSGM15) at SN 95800 80082, with Mark in the background on another candidate for the high point

Second candidate for the high point of Cefn Uchaf came to 357.4m (357.428m converted to OSGM15) at SN 95873 80107

As I packed the Trimble away after gathering data from the second high point we headed back down the track to the connecting bwlch.  The track led onto a corner of the narrow lane, where the track and lane intersect was a pool laden mud swamp.  We assessed the lane and decided that the critical bwlch lay just south of the corner in the road.  We also decided that the hill to hill traverse indicated that the critical bwlch was in the middle of the road.  So as the rain started to get heavier I set the Trimble up and we each stood about 30 metres down road from it, Mark on the southern side and me on the northern, each ready to flag down any approaching car.  Thankfully none appeared and after I took a few photos of its set up position I packed it away and we soggily made our way back up the lane to the car.

Looking south from the corner of the lane as it intersects with the track

Looking north toward the track and lane intersection

As it was only 12.20pm we decided to head into Llanidloes and visit the Red Lion, which serves Sunday roasts for £5.00, which is excellent value.  We sat with our plates full of food, mine seemed to be spilling over the sides with is always a good sign. 

Highly recommended, the £5.00 Sunday dinner at the Red Lion in Llanidloes

Postscript:  Since the survey of these hills, the LIDAR (Light Detection & Ranging) technique is now being used to produce accurate height and position for hills.  Subsequently these hills have been analysed via LIDAR and it is this result that is being prioritised in preference to that produced by the Trimble GeoXH 6000 surveys.

Survey Result:

Bryn Mawr

Summit Height:  406.2m (LIDAR)

Summit Grid Reference:  SN 94489 80295 (LIDAR)

Bwlch Height:  c 292m (interpolation)

Bwlch Grid Reference:  SN 94116 79772 (interpolation)

Drop:  c 114m (LIDAR summit and interpolated bwlch)

Dominance:  28.11% (LIDAR summit and interpolated bwlch)

Cefn Uchaf (significant name change)

Summit Height:  357.7m (LIDAR)

Summit Grid Reference:  SN 95819 80021 (LIDAR) (summit relocation)

Bwlch Height:  329.3m (LIDAR)

Bwlch Grid Reference:  SN 954212 80193 (LIDAR)

Drop:  28.4m  (LIDAR) (Trichant reclassified to Sub-Trichant) 

Dominance:  7.93% (LIDAR)

For further details please consult the Trimble survey spreadsheet click {here}