St Govan's Head is on the south coast of the Castlemartin Peninsula, in the Pembrokeshire Coast National Park, 2km south-east of Bosherston. This part of the coastline is within the Royal Artillery Corps Castlemartin Range. It is a headland of vertical limestone cliffs. The peninsula is a flat plateau consisting of Carboniferous limestone rock, about 350 million years old. The plateau was formed by marine erosion when the sea level was much higher than today, then lifted up by movements of the Earth's crust about 50 million years ago. The 13th century St Govan's Chapel [NPRN: 95059] is tucked into a cleft at the foot of the cliffs, and below it St Govan's Well [NPRN: 32502].
(Source: Pembrokeshire Coast National Park Authority, Coast Path Walk: http://www.pembrokeshirecoast.org.uk/welsh/out_and_about/walking/coastpath_walks/coastpath/map10/map10_all_info.asp).
Ian Archer, RCAHMW, 24th March 2005