Porth yr Ogof

One of the largest cave entrances in Wales where the Afon Mellte is swallowed whole.

OS grid ref SN 928124 (car park & info centre)

The cave can be viewed by a short walk from the car park.  A five minute walk beside the former river bed leads to the lower entrance at ‘Blue Pool’.


  • Carboniferous: limestone


  • OS Landranger 160, Explorer map OL12
  • Geological — BGS 1:50,000 sheet: 231 ‘Merthyr Tydfil’


  • Various publications


  • Cwm Porth Information Centre
  • Pay & display car parking
  • Entry: free


  • Steep rocky steps down to entrance, can be slippery

Transport links

  • By car — by minor roads from Ystradfellte
  • By train — nearest stations at Neath and Merthyr Tydfil

Other attractions nearby