Lewis is the northern part of Lewis and Harris, the largest island of the Outer Hebrides and the third largest in the British Isles after Britain and Ireland. Due to its flatter, more fertile land, Lewis contains three-quarters of the population of the Western Isles, and the largest settlement, Stornoway. To the west lie the isolated and uninhabited Flannan Isles. About north of the Butt of Lewis lie North Rona and Sula Sgeir, a remote group of islands which are included within Ross-shire.