[1] The route runs from Pembrokeshire eastward through South Wales to Chepstow where it enters the county of Gloucestershire and carries on through Wiltshire to its destination at Stonehenge.
A guide to the route was published in 1998: The Celtic Way: A long distance walk through western Britain by Val Saunders Evans, Cheshire: Sigma Leisure.
Key sites along the route include the following: in Pembrokeshire: Ynys Meicel, Goodwick SSI footpath, Tre-llan holy well, Carn Ingli, Pentre Ifan, Gors Fawr stone circle; in Carmarthenshire: Gwal y Filiast burial chamber, Castell Mawr, Merlin's Hill, Llanegwad, Dryslwyn Castle, Gron Gaer Hillfort, Dinefawr Castle, Carn Goch Hillfort; the Black Mountain from the Carmarthenshire and Powys border going into Glamorgan: the Carmarthenshire 'Fans' - Fan Brycheiniog ridge, Fan Hir, the Myddfai lakes, Llyn y Fan Fach and Fawr associated with the physicians of Myddfai, Cerrig Duon stone circle, waterfalls at Scwd yr Eira and Sgwd Gwladys, and the heights of Sarn Helen.
The route continues through the Vale of Glamorgan, including two significant burial chambers: Tinkinswood and St Lythans, both of which raise interesting archaeoastronomical questions.
The final section runs from Stonehenge to the Dorset Coast to set the scene for a walking route linking with France at Mont St Michel.