[1] Picws Du falls within Fforest Fawr Geopark and its prominent summit is marked by a large Bronze Age round barrow at a height of 2457 feet above sea level.

As the peak sits on the edge of the escarpment on a ridge which juts out into the valley below, the views from the summit are panoramic and extensive.

Its summit and southern slopes are formed from the hard-wearing sandstones of the overlying Pen y Fan Formation (formerly the Plateau Beds) which are of upper/late Devonian age.

The northwestern and northeast faces of Picws Du were home to small glaciers during the ice ages which gouged out the cirques of Pwll yr Henllyn and Pant y Bwlch respectively.

Access to the mountain is also possible from the car park at the foot of the road leading to the small dam on Llyn y Fan Fach.

It then follows the cliff edge across Waun Lefrith to the summit, passing several rock outcrops and gullies dropping to the lake below.

The skylark is plentiful due to the extensive rough pasture present below the main peaks which allows ground nesting of the species.

The mountain tops are above the tree line, and sessile oak is found clinging to the lower valley sides where they are sheltered from the winds.