The Brecon Beacons contains two stunning areas, which can often be confused due to the similarity of their names. The westerly one is Black Mountain or Y Mynydd Du, and it is on the Border between Carmarthenshire and Powys, above Upper Brynamman. The Black Mountains are over towards Crickhowell and Talgarth, to the east of the Brecon Beacons, and they form a border separating Wales from Herefordshire.
While either area is well worth a visit, the Black Mountain is much closer to Ystradgynlais and with limestone outcrops and tremendous views, it is a place to explore the rugged hills and try to spot the rare alkali loving plants found in the area.
There are a couple of car parks along the A4069 one with spectacular views and picnic benches and sometimes a burger or ice cream van! The other allows for exploration of old Limestone Quarry Known as Herberts Quarry, good for climbing and boldering. There are several caves in this area so be cautious with younger children.
From Ystradgynlais Follow the road to Cymllynfell at the junction with the A474 at the north of Gwaun-Cae-Gurwen, and travels through Lower Brynamman and Brynamman. The route then crosses over the Black Mountain range of the Brecon Beacons and emerges near Felindre near Llangadog. It then crosses through Llangadog and continues northeast until the junction with the A40 at Llandovery. It reaches a height of 493 m (1,617 ft) above sea level.