Wales is located on the western side of central southern Great Britain. The large island of Anglesey lies off the northwest coast, separated from mainland Wales by the Menai Strait, and there are a number of smaller islands. Most of Wales is mountainous. Snowdonia in the northwest has the highest mountains, with Snowdon being the highest peak. To the south of the main range lie the Arenig Group, Cadair Idris and the Berwyn Mountains. In the northeast of Wales, between the Clwyd Valley and the Dee Estuary, lies the Clwydian Range. The Cambrian Mountains run from northeast to southwest and occupy most of the central part of the country. In the south of the country are the Brecon Beacons and the Black Mountains in southeast Wales. The Welsh lowland zone consists of the north coastal plain, the island of Anglesey, part of the Llyn Peninsula, a narrow strip of coast along Cardigan Bay, much of Pembrokeshire and southern Carmarthenshire, the Gower Peninsula and the Vale of Glamorgan.