Wales accounts for less than one-tenth (9 per cent) of the total area of the UK, covering . Wales is mostly mountainous, though South Wales is less mountainous than North and mid Wales. The main population and industrial areas are in South Wales, consisting of the coastal cities of Cardiff, Swansea and Newport, and the South Wales Valleys to their north. The highest mountains in Wales are in Snowdonia and include Snowdon () which, at , is the highest peak in Wales. Wales has over  of coastline. Several islands lie off the Welsh mainland, the largest of which is Anglesey (''Ynys Môn'') in the north-west.