Llŷn is an extensive plateau dominated by numerous volcanic hills and mountains. The largest of these is Yr Eifl, although Garn Boduan, Garn Fadrun and Mynydd Rhiw are also distinctive. Large stretches of the northern coast consist of steep cliffs and rugged rocks with offshore islands and stacks, while there are more extensive sandy beaches on the southern coast, such as Porth Neigwl and Castellmarch Beach. North of Abersoch a series of sand dunes have developed. The landscape is divided into a patchwork of fields, with the traditional field boundaries, stone walls, hedgerows and cloddiau, a prominent feature.