SN8221 : The eastern slopes of Fan Brycheiniog and Llyn y Fan Fawr
Mountain walking; steep, exposed terrain

Fan Brycheiniog - Trig Point

802m Elevation
4m Prominence
Wales Country
Find walking friends Explore routes

Good walks are even better shared.

SN8221 : The eastern slopes of Fan Brycheiniog and Llyn y Fan Fawr

Colin Park Photo source

Overview

Fan Brycheiniog’s trig-point top is an 801.7 m subsidiary top in the Black Mountain (Y Mynydd Du), within Bannau Brycheiniog National Park, Powys. The higher main summit is Twr y Fan Foel, 802.5 m, about 290 m away along the ridge.

Fan Brycheiniog – Trig Point

This page describes the 801.7 m trig-point top, not the higher main summit of Fan Brycheiniog. The recorded high point is a grassy knoll beside the trig pillar. Twr y Fan Foel, 802.5 m, is about 290 m away along the ridge. The two tops have separate records in the Database of British and Irish Hills.

Mountain and landscape

The top lies in Powys, in the Black Mountain (Y Mynydd Du) at the western end of Bannau Brycheiniog National Park. Llyn y Fan Fawr lies below its eastern cliffs. The Black Mountains in the east of the National Park are a different range.

The mountain’s Devonian sandstone succession includes resistant summit beds. The British Geological Survey now calls these the Pen y Fan Formation; older accounts use Plateau Beds. Glaciers later helped shape the escarpments and lake basins. In clear weather, the ridge offers views towards Pen y Fan, which the National Trust identifies as southern Britain’s highest mountain.

Choosing an approach

  • From the east: the minor Trecastle road gives access to Llyn y Fan Fawr and the steep Bwlch Giedd path. Wild Trails Wales describes a circuit returning down Fan Foel.
  • From the north-west: the Llyn y Fan Fach car park serves the western ridge and two-lake circuit. The Carmarthenshire walking leaflet describes the full strenuous mountain round.
  • From the south: Glyntawe gives access to Fan Hir and longer circuits. Return to the same valley requires a planned route; descending north is not a shortcut to Glyntawe.

Storey Arms and the A4215 are not the starting points for these described approaches. Use the map appropriate to your chosen route: OS Explorer OL12 or Landranger 160.

Access and preparation

Use designated parking and keep narrow lanes, gates and passing places clear. For Glyntawe, check the T6 timetable, including your return journey. Craig-y-nos Country Park has a café and toilets south of Glyntawe; carry supplies for the mountain.

Expect exposed escarpments, boggy ground, steep paths and stream crossings. Mist, high winds, snow and ice can make the ridges dangerous. Carry a map and compass, suitable mountain footwear and clothing, and allow daylight for the whole return. The Welsh Fell Runners Association’s terrain notes highlight exposure on Fan Hir and difficult route choices in poor visibility.

Heritage

Heneb’s account of the May 2017 excavation identifies the mound beneath the trig as almost certainly a Bronze Age round barrow. Treat the remains with care and leave the stones in place.

Explore routes near Fan Brycheiniog - Trig Point

Walks starting near this hill. Open a route to check its map, distance and full itinerary.

Aircraft Crash Site - Wellington Bomber and Vampire Jet (Black Mountain range)

20.6 km ~6h Hard

View route

Usk Reservoir: Glasfynydd Forest and Dam Circuit

9.1 km ~3h 15m Moderate

View route

Pen y Fan via Corn Du from Storey Arms

7.2 km ~3h Moderate

View route

Ammanford Walk with Men Walking & Talking

View route

Route planning notes

These notes describe possible approaches. Check a route's map and access information when planning your walk.

Carmarthen Fans two-lake circuit from Llyn y Fan Fach

From the designated Llyn y Fan Fach car park, climb to the lake and follow the high ridge over Waun Lefrith and Picws Du towards Fan Foel and Fan Brycheiniog’s trig-point top. Descend via Bwlch Giedd to Llyn y Fan Fawr, then take the lower path beneath the escarpments back towards Llyn y Fan Fach and the starting track. The council’s full mountain circuit is 15 km with 712 m ascent; allow 5–6 hours. Steep rocky sections and long stretches away from shelter make this a strenuous walk.

15 km Challenging

Fan Brycheiniog via Llyn y Fan Fawr

Start on the minor Trecastle road above Maen Mawr, using available roadside parking without obstructing traffic. Cross the upper Tawe and reach Llyn y Fan Fawr, then climb the steep path to Bwlch Giedd and the trig-point top. Continue along the ridge past Twr y Fan Foel to Fan Foel, descend its steep, eroded northern spur, and return below the escarpment to the lake and outward path. Wild Trails Wales gives 8.2 km, about 3.5 hours and 400 m ascent. Boggy ground and stream levels need care.

8.2 km ~3.5 hours Challenging

Fan Hir ridge out-and-back from Glyntawe

From the Tafarn-y-Garreg area, use the signed footpath and Tawe footbridge towards Ty Henry, then climb steeply to Allt Fach and follow Fan Hir. Cross the dip at Bwlch Giedd and climb to the trig-point top. Return by the same ridge and initial approach. The ascent is sustained, with exposed edges and confusing sheep tracks in mist. A descent to Llyn y Fan Fawr creates a different valley-return route and must be planned separately.

Challenging

Western ridge out-and-back from Llyn y Fan Fach

Use the designated Llyn y Fan Fach car park and track to the lake. Climb to Waun Lefrith, follow the ridge over Picws Du, descend to Bwlch Blaen-Twrch and continue via Fan Foel and Twr y Fan Foel to the trig-point top. Retrace the full ridge route to return. This involves repeated climbing and exposed mountain terrain; it is not a short direct ascent from the lake. Leave enough time and energy for the return over the same intervening tops.

Challenging

Extended two-lake horseshoe from Glyntawe

From the Tafarn-y-Garreg lay-by (SN848170), take the lower path past Llyn y Fan Fawr to Llyn y Fan Fach. Climb Waun Lefrith and cross Picws Du, then follow the Cambrian Way branch to the trig-point top. Return via Bwlch Giedd, Fan Hir and Ty Henry to the Tawe footbridge and lay-by. The Great Outdoors gives 21 km, 986 m ascent and about 7 hours; its Fan Foel detour adds 2 km. A long mountain day with stream crossings and exposed ridges.

21 km ~7 hours Challenging
Browse more walks on the map

Make a day of it, together

Find someone to share the walk with, or organise a day out along a route you like.

Find walking friends Plan a walk here
Hill facts and local notes

Classifications

Other lists

Elevation

802m

2,630 ft

Prominence

4m

Coordinates

51.8823, -3.7080

SN825217

OS Map

160

Explorer: OL12W

At the Summit

A concrete trig pillar and nearby stone shelter stand beside the escarpment. The recorded high point of this top is a grassy knoll 1 m north-east of the pillar. Twr y Fan Foel, about 290 m away along the ridge, is the higher main summit.

Terrain & Geology

Open upland grassland boggy ground rocky and eroded mountain paths steep escarpments and stream crossings on some approaches.

Devonian Old Red Sandstone underlies the mountain, including resistant summit sandstones now termed the Pen y Fan Formation (formerly Plateau Beds). These rocks record mainly river deposition, with some shallow-marine environments. Later glaciation shaped the steep escarpments and lake basins.

Views & Scenery

Llyn y Fan Fawr lies below the eastern escarpment, with the Fan Hir ridge extending south. In clear weather, views reach east towards Pen y Fan and west along the Carmarthen Fans. Pen y Fan is the highest mountain in southern Britain.

History & Heritage

Name Origin

Brycheiniog is the historic regional name associated with the early medieval kingdom and the legendary King Brychan.

Historical Significance

A small archaeological excavation in May 2017 found that the mound beneath the trig point was almost certainly a Bronze Age round barrow. Visitor erosion had exposed its stone structure. This is separate from the cairns at Twr y Fan Foel and Fan Foel; avoid disturbing stones or enlarging shelters.

Getting There & Facilities

Parking

Choose parking for the route: the designated Llyn y Fan Fach car park near Blaenau, east of Llanddeusant; small roadside spaces on the Trecastle–Glyntawe road near SN853218 for Llyn y Fan Fawr; or the lay-by beside Tafarn-y-Garreg at SN848170 for southern approaches. Do not block gates, narrow lanes or passing places; check signs and available space. Storey Arms on the A470 is not a start for these routes.

Public Transport

The T6 Brecon–Swansea service calls at Tafarn-y-Garreg in Glyntawe, suitable for southern approaches. Check the current timetable and last return before walking. The remote Llyn y Fan Fach and Trecastle-road starts require separate travel planning.

Nearby Facilities

Take food and drinking water onto the mountain. Craig-y-nos Country Park, south of Glyntawe, has toilets, a café and pay-and-display parking; check opening arrangements. These facilities are separate from the remote mountain starts.

Safety Information

Known Hazards

  • Steep escarpment edges and exposed ridges, especially along Fan Hir; strong winds and poor visibility make route-finding more serious.
  • The path between Llyn y Fan Fawr and Bwlch Giedd is steep and rocky; the descent from Fan Foel is steep and eroded in places.
  • Boggy ground and stream crossings can become difficult after heavy rain. Do not attempt an unsafe crossing.
  • Routes descend to different sides of the mountain. Identify the return to your own start on a map before leaving the ridge; a northern descent does not lead directly back to Glyntawe.
  • Carry suitable mountain footwear, waterproofs, warm layers, food, water, a map and compass, and know how to use them. Allow enough daylight for the return.

Seasonal Hazards

Snow and ice can make steep paths and ridge edges hazardous. The narrow Trecastle road may become difficult or impassable in wintry conditions. Check the mountain forecast and road conditions before setting out.

General Safety Tips

  • Check weather conditions before setting out
  • Carry appropriate clothing and equipment
  • Let someone know your planned route
  • Take a map, compass, and GPS device
  • Carry emergency supplies: food, water, first aid kit, torch

Hills

Some common questions about the hills answered

Are there group walks up Fan Brycheiniog - Trig Point?

Many walkers use Walkmates to join or organise walks with others. You can check for group walks around Fan Brycheiniog - Trig Point through the maps

Are there other walkers around Fan Brycheiniog - Trig Point?

Activity varies by location and time, but Walkmates lets you see whether others have shared walks or shown interest in this area. Find other people through the walking friends search walking friends for Fan Brycheiniog - Trig Point search or of course create your own walk for Fan Brycheiniog - Trig Point

Can I organise a walk to Fan Brycheiniog - Trig Point?

Yes. If there aren’t any walks listed already, you can create a walk and make it available for others to join.

If you're signed up to Walkmates, you can create a walk to Fan Brycheiniog - Trig Point.

How do I find a walk up this hill?

There are often multiple ways to walk this hill, depending on experience and route preference. Walkmates helps you explore walks and routes that others have shared.

Can I suggest a new route up Fan Brycheiniog - Trig Point?

Yes. You can suggest or create routes to share with others. Walkmates focuses on the social side of walking, so routes are used to help people organise walks and explore areas together, rather than as detailed navigation tools or route libraries.

Other uses really appreciate knowledgeable walkers sharing their routes. Share your favourite route to Fan Brycheiniog - Trig Point here

The is an error or something incorrect about this hill. How do I let you know?

We always strive to keep the information on Walkmates as accurate as possible. If you find an error, please let us know through the contact form and we'll aim to correct it as quickly as possible

Location

Fan Brycheiniog - Trig Point location map

Grid reference: SN825217

View on OpenStreetMap

Opens a map in a new tab, centred on the hill.

Nearby Hills

Fan Brycheiniog - Twr y Fan Foel

Fan Brycheiniog - Twr y Fan Foel

802m

Fan Gyhirych

726m

Pen y Fan

886m

 Cribyn

Cribyn

794m

Carneddau

445m
See 5 more nearby hills