Skip to content
Skip to navigation menu


South Uist Geography

South Uist is a small island, approximately 36,467 ha, in the southern half of the Outer Hebrides or Western Isles. To the north the island is currently joined to the neighbouring island of Benbecula by an artificial causeway; however, access between the islands at low tide is possible and for much of prehistory South Uist, Benbecula and North Uist would have formed a single landmass. The channel between South Uist and Barra is more substantial and would have separated the islands from relatively early in the postglacial period. The current island is rectangular, roughly 35 km long and up to 13.6 km wide with its long axis oriented north-south. The landscape can be divided into three strips of very distinctive environments running from north to south.

South Uist mapMap of South Uist


  • A view of water lilies on one of the inland lochs of South UistThe east half of the island is an inhospitable region dominated by mountains, the highest of which is Beinn Mhor (608 metres), interspersed with large expanses of peat moorland. The coastline varies from cliffs to small sheltered bays, but the most important features are the three deep sea lochs, Loch Baghasdail, Loch Aineort and Loch Sgiopoirt, which penetrate through the mountains to the low-lying land which lies at the centre of the island.
  • Moving westward the land gradually descends, first through an area of moorland then to a region distinguished by extensive freshwater lochs separated by rocky outcrops. The central and eastern part of the islands are collectively referred to as the blacklands.
  • The west coast is characterised by a shell sand deposit known as the machair. On South Uist this extends as a continuous plain, up to 2 km wide, from the south to the north coast, and runs along the west coast of Benbecula and North Uist. Projecting from this coastline are two distinctive promontories; in the middle of the island is Rubha Ardvule, a low promontory, and at the south end is Orosay, a steep-sided tidal islet.
Harvesting the crop on the machair at North Boidsdale

Today, settlement is concentrated on the rocky outcrops between the freshwater lochs on the blacklands adjacent to the machair plain of the west coast. The islanders exploit the land in their immediate vicinity, cultivate the machair plain and use the eastern uplands as a summer grazing resource. The sea lochs of the east coast provide sheltered anchorages and small settlements oriented on fishing, or fish farming, are found scattered around their shores. Access to the Scottish mainland is also channelled through these sea lochs and has resulted in the development of a port at Loch Baghasdail.