Dinas Head is a peninsula located in the community of Dinas Cross between Fishguard and Newport, Pembrokeshire, in southwest Wales. It reaches a height of 466' (142m) above sea level, marked by a triangulation point. Dinas Head is contained within the Pembrokeshire Coast National Park and the headland is under the care of the National Trust.
Sometimes called Dinas Island (e.g. by the O.S., which names only the northernmost point as Dinas Head), it is a promontory partially detached from the mainland. On its landward side it is bordered by a swampy valley cut by meltwater overflow from a glacial lake, melt water freed from reservoirs in the Prescelly Hills by the dwindling ice. This was the same Ice Age melt-water that formed the Gwaun Valley further down the coast.