Algeria comprises square kilometers of land, more than 80% of which is desert, in North Africa, between Morocco and Tunisia. It is the largest country in Africa. Its Arabic name, Al Jazair (the islands), is believed to derive from the rocky islands along the coastline of the Mediterranean Sea. The northern portion, an area of mountains, valleys, and plateaus between the Mediterranean and the Sahara Desert, forms an integral part of the section of North Africa known as the Maghreb. This area includes Morocco, Tunisia, and the northwestern portion of Libya known historically as Tripolitania. Size and boundaries Land boundaries:Total: Border countries: Libya , Mali , Mauritania , Morocco , Niger , Tunisia , Western Sahara . Area – comparative: slightly larger than the Democratic Republic of the Congo and Saudi Arabia Coastline: Maritime claims: Territorial sea: , contiguous zone: ; exclusive fishing zone: Geographic regions The Tell The fertile Tell is the country's heartland, containing most of its cities and population. Made up of hills and plains of the narrow coastal region, the several Tell Atlas mountain ranges, and the intermediate valleys and basins, the Tell extends eastward from the Moroccan border to the mountains of the Grande Kabylie and the Bejaia Plain on the east. Its eastern terminus is the Soummam River. The best agricultural areas are the gentle hills extending 100 kilometers westward from Algiers; the Mitidja Plain, which was a malarial swamp before being cleared by the French; and the Bejaia Plain. The alluvial soils in these areas permitted the French to establish magnificent vineyards and citrus groves. By contrast, in the great valley of the Chelif River and other interior valleys and basins, aridity and excessive summer heat have limited the development of agriculture. The Grande Kabylie is a zone of impoverished small farm villages tucked into convoluted mountains. The High Plateaus and the Saharan Atlas Stretching from the Moroccan border the Tell Atlas, including the Djebel Babor formation, is the dominant northwestern mountain range. Stretching more than 600 kilometers eastward from the Moroccan border, the high plateau area (often referred to by the French name Hautes Plaines or Hauts Plateaux) consist of undulating, steppe-like plains lying between the Tell and Saharan Atlas ranges. The elevation averages between in elevation in the west, dropping to in the east. The climate is so dry that these plains are sometimes thought of as part of the Sahara.