Scotland occupies the northern third of the island of Great Britain. It is bounded by England in the south and on the other three sides by water: by the Atlantic Ocean on the west and north and by the North Sea on the east. Scotland is divided into three physical regions—the Highlands; the Central Lowlands, containing two-thirds of the population; and the Southern Uplands. The western Highland coast is intersected throughout by long, narrow sea lochs, or fjords. Scotland also includes the Outer and Inner Hebrides and other islands off the west coast and the Orkney and Shetland Islands off the north coast.