The island is part of the St Kilda World Heritage Site and home to a primitive breed of sheep.

The island covers about 96.8 hectares (239 acres) and reaches a height of 378 metres (1,240 ft), the cliffs rising sheer from the sea.

The island is formed of a breccia of gabbro and dolerites and is a single mountain peak rising from the sea-bed, without Ice-Age erosion.

[6] Along with the rest of the archipelago, Soay is owned by the National Trust for Scotland, managed by NatureScot as a nature reserve and is included it the St Kilda World Heritage Site.

[6] When the neighbouring island of Hirta became uninhabited, Soay sheep were introduced there too, and more recently they have become widely kept elsewhere as a livestock animal.