Grassholm (Welsh: Ynys Gwales) is a tiny, uninhabited island off south west Pembrokeshire in Wales, lying west of Skomer. It is the westernmost part of Wales and is known for its huge colony of gannets. Grassholm has been owned since 1947 by the Royal Society for the Protection of Birds, and was the first reserve the Society ever bought.
Boats sail to Grassholm from Martin’s Haven on the mainland.
Gresholm – From ‘A Topographical Dictionary of Wales’ (1849)
GRESHOLM, an island, situated off the hundred of Rhôs, county of Pembroke, South Wales, six leagues (N. W.) from Milford Haven. This is one of the largest and most central of a line of isles and rocks which extends in a western direction, at some distance from Skomar Isle on the coast of Pembrokeshire, and terminates at the “Smalls,” on which is a lighthouse. Gresholm is lofty, steep, and nearly circular, and is generally the first land seen on approaching Milford from the west. Between this island and the “Smalls,” but nearer the latter, is a ledge of rocks, about a mile long, visible at low water, and named the “Hats and Barrels;” and about a league from Gresholm, nearly in the same direction, are others, called “Skettle,” or “Kettle bottom.” All these rocks are extremely dangerous to navigation, as the sounding is upwards of thirty fathoms immediately to the north and south. At the distance of a league from Gresholm, north-by-west, lies a sunken rock, named the “Pope;” and three leagues to the north-east is the “Augre bank,” or “Taradr,” connected with the “Mascus,” a piece of foul ground which is occasionally dry at low water. This range of rocks presents such opposition to the flood tide, that it is generally high water on the coast from two to four hours before it manifests itself amongst them, and the ebb tide is of course equally late.