Bannau Sir Gaer - Picws Du

Bannau Sir Gaer – Picws Du

Picws Du rises to 749.1 m above Llyn y Fan Fach in the Black Mountain, in the western part of Bannau Brycheiniog National Park. A cairn marks its summit. The grassy ridge gives way abruptly to the cliffs above the lake, which are the defining feature of this walk.

Choose a summit route

The northern circuit starts at Llyn y Fan Fach car park near Llanddeusant. Walking Britain’s route 3559 follows Afon Sychlwch to the col east of Picws Du, crosses the summit, then returns along the western escarpment and down to the lake. Its published figures are 8.6 km, 485 m of ascent and 4 hours.

A different circuit begins at the small roadside parking area at SN853218, east of Llyn y Fan Fawr. Walking Britain’s route 3563 climbs through Bwlch Giedd, includes Fan Brycheiniog and an out-and-back visit to Picws Du via Fan Foel, then descends north of Fan Foel to return beside the lake. It is 11.5 km with 606 m of ascent; the published time is 5 hours 10 minutes. Allow more time for stops and difficult conditions.

The track to Llyn y Fan Fach offers a shorter lakeside outing without climbing Picws Du. A lake walk, the western ridge circuit and the longer two-lake routes have different distances and demands.

Ridge, weather and navigation

Expect steep path sections, loose stones near the escarpment, open grass and wet ground. Keep well back from the cliffs, particularly in wind or mist, and keep dogs close around the edges and sheep. Carry a map and compass and know how to use them; the remote terrain and branching paths demand care when cloud hides the landmarks.

Snow or ice can obscure paths and make steep ground much more serious. Cornices may overhang the escarpment: stay well away from the snow edge. Winter conditions require appropriate skills and equipment, and short daylight needs extra planning.

Access and facilities

Approach the northern car park through Llanddeusant on narrow lanes, with an uneven final approach. Parking space is limited; follow current signs and keep access clear. The car park has an information panel. Bring supplies for the walk; Llandovery has shops and cafés. Plan rail and onward transport separately, checking current connections through Traveline Cymru.

Landscape and neighbouring tops

The rocks around the lake and cliffs belong to the Devonian Old Red Sandstone, including the Brownstones and Plateau Beds formations. Ice shaped the deep hollow now occupied by Llyn y Fan Fach.

Waun Lefrith is the lower top to the west. Fan Foel and Fan Brycheiniog lie to the east, beyond an intervening descent and climb. Fan Brycheiniog’s highest point, Twr y Fan Foel, is distinct from its nearby trig-point top.

Bannau Sir Gaer means “Carmarthenshire peaks”. Welsh folklore associates the lake below with the Lady of the Lake and the Physicians of Myddfai.