Brecon
Ogof Ffynnon Ddu
(Cave of the Black Spring)
Upper Swansea Valley
South Wales
 
 
 
Caving and pot holing is a popular activity in the Brecon Beacons but this is a dangerous sport and should only be undertaken in the company of experienced cavers.
 
If you would like to explore this cave the best people to contact for access is the Ogof Ffynnon Ddu Management Committee of the South Wales Caving Club.
 
- Address:
1-10 Powell Street, Penwyllt, Pen-y-Cae, Swansea SA9 1GQ.
Tel: 01639 730613
 
Ogof Ffynnon Ddu (OFD) is now part of the Ogof Ffynnon Ddu National Nature Reserve which includes the ruined remains of a former brickworks. The site has several kilns, quarry workings and tramroad tracks. The terrace of workers cottages is now occupied by the South Wales Caving Club.
 
The Cave System
The OFD spreads under a hillside in the area surrounding Penwyllt in the Upper Swansea Valley and has three entrances. With a depth of 900 feet (274 m) and at least 31 miles (50 km) long, it is the deepest cave in the UK and the second longest in Wales.
 
One of the largest cave systems in Britain, the passages and chambers of the OFD weave a long and tortuous path beneath the east side of the Tawe Valley. The stream passage cuts through black limestone producing waterfalls, rapids, deep pot holes and scalloped walls.
 
The system is divided into three parts, the lowermost (western) section is referred to as Ogof Ffynnon Ddu I (or simply OFD I); the central section as OFD II and the uppermost (eastern) section as OFD III.
 
Wildlife
An assortment of specialized wildlife has developed underground including cave shrimps and the pale blanched trout endemic to pure underground fresh water courses with sufficient plankton.
 
Above ground, deep cracks in the vast expanse of stony moorland provide habitats to plant life, including the lily of the valley and wood anemone, and mossy saxifrage (Saxifraga hypnoides) grows on the limestone outcrops.
 
Contact & Further Information
Ogof Ffynnon Ddu Management Committee
South Wales Caving Club
 
 
Google Maps - Ogof Ffynnon Ddu