Add marker to map:              help
Marker Notes X

To add your own marker to the map, click on the appropriate symbol below the map, then click again at the location required on the map (using the crosshairs).

Logged-in registered users only...
When you add a marker, a pop-up box should then appear on the map - fill in the elevation (if known) and a brief description of your marker, then click [save].

To view previously saved markers which fall within the bounds of the map, click the show link (you may need to repeat this if you zoom or pan away from the current position on the map).

Name:Mynydd Twyn-glas
Hill number:2292
Height:472m / 1549ft
RHB Section:32C: Neath to Chepstow
County/UA:Caerphilly (UA), Torfaen (UA)
Class:Marilyn, Hump, Tump (400-499m), Clem
Grid ref:ST 26001 97850
Summit feature:knoll 35m N of trig point
Col:219m  ST227988  
OS map sheet(s):(1:50k) 171
(1:25k) 152
Observations:knoll is 50cm higher than base of trig point; knoll 30m WNW of trig point is 30cm higher; trig point is at ST 25996 97816
Survey:Abney level
GPS data:show GPS entries for this hill

Show Map
(Please be considerate with your usage of the OS map pages, as there are daily limits)

View on: Geograph  OS Maps  Streetmap  Magic  NLS  OSM

Full screen map
Switch to Bing Maps view
(Please be considerate with your usage of the Full Screen/Bing Maps pages, as there are monthly limits)

Resize map: portrait / landscape / reset

Map Help, This page uses the Ordnance Survey OpenSpace API
which does not include Explorer (1:25000 scale) mapping.

Show/hide GPS File for mountains/markers shown

Show/hide GPX File for mountains shown

No summit photo available
Hill summit
No portrait photo available
Hill portrait

To contribute a summit or portrait photo for a hill
please contact the hillsummits website

N.B. Some hill summits are on private property or on land where there is no public right of way.  Permission should be sought from the landowner where access to a hill summit is through private land.
Please report via the contact page any logs you see below which describe or encourage acts of trespass, and mention the hill number and hill name.

Logged Descriptions  (logged by 216 users, only the latest 50 shown - Show all)ByDate of Ascent
From Mountain road to the East, up to the mast then tracks to top.NormanW06/10/2019
Cwmbran - Mynydd Twyn-glas - Griffithstown.Mark Jackson05/10/2019
10.45 gentle stroll up from where I kipped the night above upper Cwmbran where a gorgeous waning gibbous moon rose shortly after I arrived.vegibagger21/07/2019
1/3 Pylons. Extremely clear evening so cracking views from the trig.penbet27/06/2019
Walk up from Cwmbran station via a walk along the canal to Sebastopol then up the eastern end of the hill. Nice views of Pen y Fan and the central Beacons, although the flat summit lacks much drama itself. From here I had a pleasant walk south along the ridge to Twmbarlwm hillfort (well worth the visit) before dropping down to Risca to get a bus back to Newport.thesweetcheat01/06/2019
Parked in car-park - keep an eye out for motorbikes on the hill.Stevooo26/05/2019
Decided to avoid the stony track by setting off across the common, where I came across a 'Boundary of Minerals'stone before finding Gill's benchmark close to the masts.SteveG10/01/2019
Parked at Mountain Air car park and followed path up. Great views and beautiful day for it.Hippy7718/11/2018
Dry but a bit chilly - icy puddles on the track above Cwmbran.Speleoprez30/10/2018
Easy hike up from the east, starting from car park a short distance above an open gate to the west of the road.Topographer5702/10/2018
Parked at the Corner and followed the very stony track - can be avoided by walking on the grass. Not a very inspiring hill but apart from trail bikers only saw one dog walkerclimbingkershaw15/09/2018
From cattle grid along track - gate was open so could have driven virtually all the way. Overcast.SS15/08/2018
Parking on the carp park on Mountain Road to the E then easy climb along well marked path. Great views on the way up. Pillar in good condition, great views at the summit, not a soul around :) Clem, Hump, Marilyn, Pedwar, P30 Tump.griefmiester01/08/2018
Followed the pylons up the hill. Counted my way up on a very hot day. Reckoned they are about 100 yards apart. Last bit of path chalky/sandy.elizyanne14/07/2018
1/3 Parked by cattle grid to the west and then followed the track by the pylons. Just one brief appearance by a trail bike and one dog walker, otherwise just us, the sheep and the skylarks. More enjoyable than expected given some previous comments.milimana17/05/2018
From Twmbarlwm north along the ridge path/track across Mynydd Maen to the buildings west of the summit, then east up the path to the trig pillarMariana Trench11/03/2018
An apocalyptic Marilyn? An unpleasant and tedious walk on a stony track alongside a row of pylons, past two masts, and serenaded by the dulcet tones of gaggles of trail bikes. The most exciting part was spotting a benchmark on what appears to be an ancient standing stone.Gill28/01/2018
Along track and pylons from west - easy parking at road cornerMark Sims10/01/2018
From car park in Upper Cwmbran via reservoir.lenman28/12/2017
With TJB from car parking to west via easy trackstrimarc215/11/2017
2/8M parking to the west good track all the way to the top.robertphillips09/11/2017
Laborious progress up from the east in the dark, wind and rain slip-sliding about trying to dodge the puddles and not really succeeding.Alex C30/09/2017
Pleasant walk up from the East. Apart from nearly getting run over by some idiot in a trail bike it was a good hill. Fine views South to the Severn estuary.isabelle19/08/2017
Met a public spirited gentleman on top, painting the trig pillar white.ngthack10/04/2017
With: hb; Walked from car park at ST237980 along very gentle track past the aerials up to the summit. Extensive heather coverage in flower surrounding the trigpoint.Ian Baines26/08/2016
With: ib; Helen Baines26/08/2016
From Upper Cwmbran, 278981 (picnic table symbol, it's a brave person who would picnic up there!). Clear to 450m, smir, calm, limited views by the top.iangalbraith04/07/2016
from west parking 236976. best way to drive there is from Pantside as road wider. previous watson report paints a dim picture, suggest you narrow your camera angle, or re-visit. unless you are welcist.dicky29/05/2016
Park at roadside carpark and walked up the side of the hill rather up the rocky gravel path. Walked up to mast and then on to trig point. Great views in every direction. With stig_nest.Laura.W20/03/2016
As described by Laura.W. From c/p on mountain road. A burnt out car gives some indication of the area dare i say. The rubbish even more so. Folks cant you just take it with you? For your kids sakes? Hill also badly scarred by motorcross bikes. I just feel for the people who call this their local hill. The views are stunning but the lasting impression is one ofa bit of a mess.stig_nest20/03/2016
Started from road side car park on Mynydd Maen Common (ST 23595 97652). Looked an uninteresting hill heading west towards aerials and trig point. Bit more interesting visiting all possible high points around trig. Lovely views on return down source of two tributaries for Nant Gwyddon.SteveSmith08/01/2016
Along track from the west. A fine herd of black cattle encountered en rout, with two docile bulls.jenx19/11/2015
With Jenx, 6/7 today. Took the track walk in as most others. Interesting herd of Welsh Black cattle with two bulls to negotiate, all very docile and quite. Trig on top reminding us very much of North York Moors scenery. Just on an hour to wlak there and back.nordicstar19/11/2015
Part of LDWA Ravens Dare 26-mile challenge walkliljonb03/10/2015
Evening walk with Ruth, Paula and Stuart, great viewskevandroo02/10/2015
Started out from the Mountain Road car park above Cwmbran, soon escaping the confines of the town to enter some good walking territory. Done as part of a ridge walk route which also took in Twmbarlwm. Beautiful sunny day, from which even the numerous pylons crossing the plateau could not detract.Cas-gwent28/09/2015
A 30 minute walk up the track from the sheepfold at ST 236980. This was at the end of a long day bagging Marilyns...G4OBK (Phil)14/08/2015
Followed track and pylons, good view in all directions from the top.PeterD18/07/2015
Easy parking at 236981 and then a 65 minute walk to the trig with GB.bolton15/07/2015
Parked at the side of the track at ST23611 38053 Good service vehicle tracks to trig point & nearby summit. (PM)gerrybowes15/07/2015
As per GB/Bolton in nine days time!tim74706/07/2015
. CreakingHiker06/07/2015
Form the summit of the Cwmbran mountain Road- large car park, a worn path direct to a relay station, joining a broad track. Back same way- a walk over to Risca looked as thought it would be good. About 80 mins, enjoyable.pwheeler01/05/2015
I wondered lonely as a cloud among a host of pylons. Parked on the road and followed the pylons over the much grazed common to the gas works next to the telecoms masts. On way back so bored that I started counting the different types of stones used to construct the track - got up to 7, nine if you include brick and concrete. Fourth tick of the day but Mrs Mindlessflogger refused to do any more. For once I agreed with her. Did see some (daring) Ravens.mindlessflogger07/02/2015
1/7 First one of long day park at entrance to long drive up to radio masts take right hand fork behind masts to get to trig pointFergalh30/11/2014
Part of Valleys 100Rob Pen y Garn24/05/2014
First hill on the valleys 100robert24/05/2014
With Val. Parked Blaen Bran, up through woods to ridge. Down East ridgemike.hoult04/12/2013