Porth yr Ogof

This site has been particularly busy recently – why not think about visiting another part of the Geopark or wider National Park at the moment?

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