Mapping Mountains – Significant Name Changes – 200m Twmpau and Y Trechol – The Dominant Hills of Wales

 

Gaer Fawr (SJ 223 129) 

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

Gaer Fawr (SJ 223 129)

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

200m Twmpau – Welsh hills at or above 200m and below 300m in height that have 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.  The list is authored by Myrddyn Phillips, with the word Twmpau being an acronym standing for thirty welsh metre prominences and upward. 

200m Twmpau by Myrddyn Phillips

Y Trechol – The Dominant Hills of Wales – Welsh P30 hills whose prominence equal or exceed half that of their absolute height.  With the criteria for Lesser Dominant status being those additional Welsh P30 hills whose prominence is between one third and half that of their absolute height.  The list is authored by Myrddyn Phillips with the Introduction to the start of the Mapping Mountains publication of this list appearing on the 3^rd December 2015, and the list is now available in its entirety on Mapping Mountains in Google Doc format. 

Y Trechol - The Dominant Hills of Wales by Myrddyn Phillips

The hill is adjoined to the Carnedd Wen group of hills, which are situated in the southern part of North Wales (Region A, Sub-Region A2), and it is positioned with minor roads to its north and west, and the B4392 road to its south-east, and has the village of Cegidfa (Guilsfield) towards the south. 

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 appeared under the transposed name of Gaer-fawr Hill, which is a prominent name that appears adjacent to the summit of this hill on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map.

Gaer-fawr Hill

219m

SJ224130

126

240

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 prominent name that appears adjacent to the hill on the Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map.  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.  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 these maps along with local enquiry that prompt the change in the listed name of this hill.

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 records the name Gaer Fawr adjacent to the summit of this hill. 

Extract from the Ordnance Survey Draft Surveyors Map

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 Welsh 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 also this map that places the name Gaer Fawr adjacent to the summit of this hill. 

Extract from the Ordnance Survey One-Inch 'Old Series' 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 200m Twmpau and Y Trechol – The Dominant Hills of Wales is Gaer Fawr and this was derived from a variety of sources including the Ordnance Survey Draft Surveyors Map and the Ordnance Survey One-Inch ‘Old Series’ map.  The Hill part of this name that appears on the contemporary Ordnance Survey 1:50,000 Landranger and 1:25,000 Explorer map is a later addition, with local pronunciation favouring the exclusion of this word with the use of Gaefer being predominant. 

 

The full details for the hill are:

Group:  Carnedd Wen

Name:  Gaer Fawr 

Previously Listed Name:  Gaer Fawr Hill   

OS 1:50,000 map:  126

Summit Height:  217.6m (converted to OSGM15, Trimble GeoXH 6000) 

Summit Grid Reference:  SJ 22394 12995 (Trimble GeoXH 6000)               

Bwlch Height:  138.7m (LIDAR) 

Bwlch Grid Reference:  SJ 21991 13145 (LIDAR) 

Drop:  78.9m (Trimble GeoXH 6000 summit and LIDAR bwlch) 

Dominance:  36.26% (Trimble GeoXH 6000 summit and LIDAR bwlch) 

 

Myrddyn Phillips (July 2026)

Mapping Mountains – Trimble Surveys – Carnedd Wen

 

20.11.25  Gaer Fawr (SJ 223 129, previously Trimbled)

Gaer Fawr (SN 223 129)

Gaer Fawr stands as a large mound of a wooded hill on the periphery of Guilsfield.  The trees hide its true significance as one of Wales’ great ancient hill forts.  When occupied it had up to five lines of ramparts, with some 8m in height.

The wood surrounding the hill is now managed by the Woodland Trust and today’s visit was with my cousin Lynn.  Since our last visit in May 2021, Lynn had donated a large sum to the Woodland Trust from a trust fund set up in memory of her late husband; Dave.  Part of the donation went toward installing a bench overlooking the eastern aspect of the hill toward Cefn Digoll off in the distance.  Therefore, as well as enjoying Lynn’s company whilst taking in a small walk, she wanted to show me the bench set up in Dave’s memory.

Having left my car in the parking area beside a small quarry we headed back down the narrow lane that leads toward the south-westerly lower part of the hill.  The weather was set fine, albeit with a chilled easterly breeze.  However, during our walk we were sheltered from this in the wood.

There are a number of paths through the wood, all seem to connect with ones leading to the summit which I’d previously Trimbled.  Our route for the day led back down the narrow road to a gate giving access to the lower eastern part of the wood. 

Lynn on the path heading through the wood

It was good to be out with Lynn again, a person whose company I’ve enjoyed on small walks over recent years.  The path circled the easterly part of the wood, gaining height as it did so, before swinging up in to the canopy of trees that shone dappled light whenever the sun broke through intermittent cloud. 

The bench set up with one of Lynn's donations to the Woodland Trust

Our route led us straight to the bench.  It was an ideal place to stop and rest.  From this position a gap in the trees looked out toward the east.  Just behind us another path led up to connect with one of the main routes to the summit.  The bench had been placed in a quiet spot, one for rest and contemplation.  A small plaque on it had an inscription from one of Lynn’s favourite poems which she read for me; Fern Hill by Dylan Thomas, ‘and once below a time I lordly had the trees and leaves’.  I took a few photos before we left to head up the path toward the summit. 

The plaque in memory of Lynn's late husband

Although the summit area is open there is no extensive view due to surrounding trees.  However, it is a beautiful place to visit and especially so in May when blue bells adorn the ground. 

The summit of Gaer Fawr (SJ 223 129)

We both wandered, me enjoying the dappled low light casting deep shadow and emerald colour through the trees and Lynn looking out through the trees to the lands beyond.  We left heading down to visit the large terracotta wild boar that commemorates the bronze boar helmet found at this site that is positioned near the top of the ancient north-east entrance. 

The terracotta boar

Leaving the wild boar we took the path down, opting for the longer route that contours the lower part of the wood leading back to the small quarry and the awaiting car.  By the time we arrived the temperature had chilled with late afternoon heralding another cold frost encrusted night. 

    

Survey Result: 

 

Gaer Fawr (significant name change)

Summit Height:  217.6m (converted to OSGM15, from previous Trimble GeoXH 6000 survey) 

Summit Grid Reference:  SJ 22394 12995 (from previous Trimble GeoXH 6000 survey) 

Bwlch Height:  138.7m (LIDAR)

Bwlch Grid Reference:  SJ 21991 13145 (LIDAR)

Drop:  78.9m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  36.26% (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

 

For details on the 1^st survey of Gaer Fawr

For details on the 2^nd survey of Gaer Fawr

For details on the 3^rd visit to Gaer Fawr

 

 

For further details please consult the Trimble Survey Spreadsheet

Mapping Mountains – Trimble Surveys – Carnedd Wen

02.05.21  Gaer Fawr (SJ 223 129, previously Trimbled)

One of the paths leading to the summit of Gaer Fawr

My cousin; Lynn had suggested a walk to the top of Gaer Fawr a number of weeks ago.  She had visited this hill previously and wanted to visit when the hill is carpeted in bluebells.  It was also where she scattered her late husband’s ashes.  Since doing this she hadn’t revisited, so as well as a bit of good cousin catch up time it was also an opportunity for Lynn to reflect. 

The forecast for the day predicted showers breaking out mid-afternoon and therefore it seemed we had no rush to make an early morning start.  We were walking by 11.30am having squeezed my car in to the last remaining space in the first of two parking possibilities on the narrow lane just to the west of the hill’s summit. 

Not yet carpeting the whole hill but still beautiful to see

However, the sky already gave signs that the morning’s sunshine was quickly being replaced by cooler climes with grey shower cloud soon appearing.  I’d visited this hill twice before, the first with Alex Cameron in August 2015 and the second with Linda during the recent winter lockdown.  On the second visit Linda and I walked from our respective front doorsteps in Welshpool, and met at the top of the Windmill Lane for the continuing walk toward the hill. 

Today’s visit Lynn and I accessed the hill through one of the main entrances, but used a path I had not been on before that gained height near the south-westerly ridge of the hill.  As we set off up the hill dappled light still clung to the path with the wood that encloses the hill looking beautiful with fresh green leafed trees reaching for the sky and the bluebells giving colour to the foreground. 

The morning's sunshine quickly replaced by shower cloud

There were a number of people on the hill, some picnicking, others out with dogs, but the one common thing mentioned were the bluebells and that it was still a week or so too early before the whole hill is carpeted in their colour.  However, they were there and although not in dramatic fashion, they added colour to our walk. 

The path slowly gained height through the wood weaving its way under the overhead canopy and beside a myriad of blue and white flowers.  I was glad Lynn had suggested this walk, my plan otherwise was more blogging, but a couple of hours in good company on a hill is always welcome. 

Lynn at the summit of Gaer Fawr

The summit area of Gaer Fawr is relatively open compared to the various paths that approach it, and when we arrived I visited the two places that vie for its highest point.  Lynn found the spot where David’s ashes had been scattered and I left her there to gather her thoughts whilst I contentedly wandered around the upper part of the hill. 

The bluebells at the summit area of Gaer Fawr

Lynn re-joined me a few minutes later and we continued down to where the terracotta wild boar is placed.  This is always a welcome site even if it is now sadly missing two of its ears! 

The terracotta wild boar

By now a few rain drops were reaching the hill and the earlier sunshine had been swept away and replaced by menacingly grey cloud.  At this point the rain did not materialise beyond a few drops, but ten minutes later it began again.  Being in the wood, we at least had a semblance of shelter; it didn’t seem to affect Lynn as she was happy stopping and looking at flowers, whilst I had my thoughts pinned on the car and getting back when still relatively dry. 

Thankfully what could have been a cloud burst never materialised and our progress back to the car became a leisurely plod.  Sitting on a bench, chatting, looking at flowers and soaking in the ambiance of the wood. 

 

Survey Result:

 

Gaer Fawr (significant name change)

Summit Height:  217.6m (converted to OSGM15, from previous Trimble GeoXH 6000 survey) 

Summit Grid Reference:  SJ 22394 12995 (Trimble GeoXH 6000 survey) 

Bwlch Height:  138.7m (LIDAR)

Bwlch Grid Reference:  SJ 21991 13145 (LIDAR)

Drop:  78.9m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  36.26% (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

 

For details on the 1^st survey of Gaer Fawr Hill

For details on the 2^nd survey of Gaer Fawr Hill

For details on the 4th visit to Gaer Fawr

 

 

For further details please consult the Trimble Survey Spreadsheet

 

 

  

Mapping Mountains – Trimble Surveys – Carnedd Wen

01.03.21  Gaer Fawr (SJ 223 129)

Gaer Fawr (SJ 223 129)

Glorious early spring sunshine and warmth has dominated over the last two days, but at this time of year conditions can be easily transformed and this morning I set out from my home following the canal towpath as mist and murk hugged the waters and surrounding countryside. 

Misted scene beside the canal towpath

Mist can bring a beauty all its own and as I followed the Rhallt and then Gungrog Fawr Lanes steeply uphill I stopped occasionally to just listen.  Without a breath of breeze and no extensive view one’s world becomes enclosed and mine this morning concentrated on the delicate ebb of a slow flowing brook, whilst bird song wafted from a near hedgerow and almost silent drops of moisture fell from overhanging trees scattering as they did so on the muddied track at my feet.  It was a morning to savour, albeit a bit chilly compared to the last couple of days. 

I was at the crossroads bisecting the Gungrog Fawr Lane and Windmill Lane at 9.15am and waited for Linda to emerge out of the mist five minutes before our pre-arranged meeting time.  Good with time this girl is! 

Our plan for the day was to follow lanes and footpaths down in to Guilsfield and then head up Gaer Fawr, which I’d visited once before in August 2015 along with Alex Cameron during a bagging bonanza of local hills.  It was then awash with late summer green, today the mist lingered. 

Prior to this visit I’d analysed the hill’s numerical details with LIDAR.  Producing an accurate height and position for its connecting bwlch and a height and position for its summit, with the LIDAR summit position being 18 metres from where the Trimble gathered data on my previous visit.  I’d come prepared with ten figure grid references for each and hoped that the lack of summer growth would help in determining the hill’s high point. 

LIDAR image of Gaer Fawr

We followed the paved road past Trelydon Hall and continued toward a quiet lane leading in to Guilsfield, here we diverted to a footpath leading in to a wood which led us to Glanllyn Pool.  This was a surprise as my Ordnance Survey map doesn’t show the pool, but there it was bathed in morning mist resembling an image from the Florida Everglades. 

Glanllyn Pool

Surprises are often welcome additions to any walk and Glanllyn Pool was certainly so.  We happily sauntered beside its waters for ten minutes across the greened and partly muddied walkways and duckboards leading to one of the village’s housing estates.  I then wanted to take us in the wrong direction, which I’m prone to do on occasion. Even with an OS map in hand my navigation skills and sense of direction can be found wanting.  Linda recognised one or two houses and a quick enquiry with a postwoman put us on the right route toward our hill. 

Gaer Fawr is impressive; however its ancient earthworks are now immersed in woodland which although attractive has distracted from the earthen embankments and ditches.  The walk to its summit is enjoyable though and today the misted scene added tranquility to the already quiet nature of this part of Wales. 

Heading up Gaer Fawr

There are a number of paths leading up to the semi-open summit area and once there I set about determining its high point.  I collected data from two points whilst Linda sat patiently on a tree stump as the Trimble ever so slowly crept down to the 0.1m accuracy level before data should be logged.  By the time the second data set was gathered and stored the mist had risen and sun was breaking through the overhead grey cloud cover. 

The summit area of Gaer Fawr

Once the Trimble was packed away we continued over the hill to visit the terracotta wild boar which is an enlarged replica of a bronze wild boar found on the hill during excavation.  Beyond the terracotta piggie we followed a steeply descending path that eventually contoured the lower southerly slopes before finding ourselves back on our inward lane. 

The terracotta wild boar

Glimpse of sunshine on the descent from Gaer Fawr

We then retraced our steps back to the delights of Glanllyn Pool, followed by the Windmill Lane just beyond Trelydan Hall, meeting and chatting with a myriad of dog walkers, goats, horses and of course the occasional sheep! 

The delights of Glanllyn Pool

All that remained was the walk back on public footpaths across fields adjacent to the Windmill Lane to the top of the Red Bank and then down through the grounds of St Marys toward the centre of Welshpool.  It proved yet another excellent little expedition, this time to the wild and salubrious surrounds of Guilsfield.  

 

Survey Result:

 

Gaer Fawr (significant name change)

Summit Height:  217.6m (converted to OSGM15, from previous Trimble GeoXH 6000 survey) 

Summit Grid Reference:  SJ 22394 12995 (Trimble GeoXH 6000 survey) 

Bwlch Height:  138.7m (LIDAR)

Bwlch Grid Reference:  SJ 21991 13145 (LIDAR)

Drop:  78.9m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  36.26% (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

 

For details on the 1^st survey of Gaer Fawr

For details on the 3^rd visit to Gaer Fawr

For details on the 4th visit to Gaer Fawr

 

For further details please consult the Trimble Survey Spreadsheet

 

 

 

  

Mapping Mountains – Trimble Surveys – Carnedd Wen

08.08.15  Gaer Fawr (SJ 223 129) and Pt. 172m (SJ 214 125, not Trimbled)  

Gaer Fawr (SJ 223 129)

A hill bagging day in the company of Alex Cameron which concentrated on summits, so the more esoteric side of surveying bylchau would have to wait another day.  The singular traverse of the summits started on the outskirts of Cegidfa (Guilsfield) and continued through the small community of Deuddwr, before heading toward the land above Llanymynech and ending up on the outskirts of Oswestrry (Croesoswallt).

Our first hill of the day is a rather stunning little gem; Gaer Fawr, this hill is positioned on the outskirts of Cegidfa (Guilsfield) and is heavily wooded.  It is a hill that I have seen on countless occasions but up until today, never visited.

We parked at the top of the Gwreiddyn Lane at SJ 219 125 where three or four cars can be left in the area of a small disused quarry.  This is an official parking place as two paths start from it, both heading in opposing directions around the hill.

Gaer Fawr dates from around 800BC with work continuing on it for another four centuries, and originated as a small summit fort that over time was extended, taking in two massive entrance ways created with graded approach ramps and defended gateways.  The construction has up to five lines of ramparts over 8m (26ft) high.  Much of this is now swamped in undergrowth with the whole area of 5.8 hectares (21 acres) covered in woodland.

Information board showing an artist's impression of Gaer Fawr

We followed the northern path which gains steady height around the western fringes of the hill, the sun shone from a blue sky and occasional bird song sprang from our surrounds.  Occasionally small animal paths tempt you straight up the hill but we continued on the main path as it swung around to the north-west of the summit.

Heading toward the summit of Gaer Fawr

It seemed that we had this rather special place all to ourselves as the world went about its business below.  Nearing the top the path reaches a relatively flat area where a beautiful terracotta wild boar is on display, this is perched on the ground beside a secret gateway into a tree in the form of a very small door.  The statue commemorates a small hollowed bronze boar which was found at, or near to, the hill fort, this is now displayed in the National Museum of Wales.

Statue commemorating the hollowed bronze boar of Gaer Fawr

The secret doorway

Only a short distance from the rather beautiful piggy is the summit area of the hill, part of this consists of a small open space where a single tree is guarded by a stone circle which has been laid around its base, this is not ancient or in the form of what we would consider a stone circle, but more a laying of small rocks around the tree, however it does give an added mysteriousness to the place as do a number of objects that hang from the lower branches.

Tree with stone circle

Alex and I assessed the land around this tree and an area about 60 metres from it which was more overgrown but which we considered higher.  I placed the Trimble on the top of my rucksack to give it elevation above the undergrowth and the waiting game began.  After 10 – 15 minutes it had crept down to 0.12m accuracy and a short time later I pressed ‘Log’ and it started gathering data. 

Gathering data from the summit of Gaer Fawr

On the periphery of the summit area the land plunged down into sunshine which occasionally broke through the canopy of trees, with the whole place being peaceful and seemingly forgotten.

Sunlight through the canopy of trees

Once five minutes of data were collected we measured the offset as o.45m which will be taken off the processed result, and I packed the equipment away.  Our descent was on the south-western path which headed straight down to the awaiting car.

Once back at the car we looked at the land on the opposite side of the lane as this led up to our next summit, Alex contemplated a direct approach through forestry.  I favoured a simpler, albeit less exciting approach via a footpath to the north of the hill.  Thankfully we decided on the latter and jumped in the car to drive north and then westward to park in a small pull-in spot.

Our next hill is listed as Bryn Trawscoed-hen in the P30 list that appears on Geoff Crowder’s v-g.me website, this is an invented name and is partly taken from the farm just to the south-west of the hill’s summit. 

Pt. 172m (SJ 214 125)

By the time we had walked up the lane to a track which led through the yard of Trawscoed Farm the morning had warmed up and the sun started to beat down.  Beyond this farm we had a chose and opted to walk down a field and over a fence that gave us access into another field which led up beside a hedge toward the copse of trees at the summit of this hill.

During this time we kept quiet as we didn’t want to disturb any farm dogs or farmers, once beside the copse of trees we headed toward its corner expecting to find the high point of the hill in a field, clear of trees, as indicated by the placement of the 172m spot height on current Ordnance Survey maps.  We were surprised to find this part of the hill embedded in trees with the wood much larger than indicated on the map. 

As we clambered over a fence past nettles and brambles it was obvious that I would have to forsake having the hill Trimbled as the tree coverage and undergrowth was extensive, I happily took a photo of Alex on what we deemed to be the high point of the hill and out of the wood we scampered.

Alex at the high point of Pt. 172m

Looking back toward the summit

Heading to the track through Trawscoed Farm and back to the car

The view of Gaer Fawr Hill from the track heading to Trawscoed Farm

Our next stop was Y Gaer which is situated to the north of these two hills and its walk and Trimble survey will be described in another blog post.

Survey Result:

Gaer Fawr (significant name change)

Summit Height:  217.6m (converted to OSGM15, Trimble GeoXH 6000)

Summit Grid Reference:  SJ 22394 12995 (from subsequent Trimble GeoXH 6000 survey)

Bwlch Height:  138.7m (LIDAR)

Bwlch Grid Reference:  SJ 21991 13145 (LIDAR)

Drop:  78.9m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  36.26% (Trimble GeoXH 6000 summit and LIDAR bwlch)

For details on the 2nd survey of Gaer Fawr

For details on the 3rd visit to Gaer Fawr

For details on the 4th visit to Gaer Fawr

For further details please consult the Trimble Survey Spreadsheet click {here}