Mauritania is a country in West Africa bordered by the Atlantic Ocean and the countries of Western Sahara, Algeria, Mali and Senegal. Most of Mauritania is desert, with alternating areas of plains and sand dunes. The southeast area of the country contains some brush and savannah regions along with small amounts of tropical forest.
The northernmost two-thirds of Mauritania consists of part of the Sahara Desert. This is an area with little water or vegetation. Sand dunes in this part of the country shift with the wind, constantly changing the physical geography of the area.
South of the Sahara Desert is an east-west belt consisting of steppes and grasslands known as the Sahelian Zone. While this section of the country also contains sand dunes, they are often covered with grasses.
The Senegal River Valley experiences greater rainfall than in any other region of the country. The Senegal River is the only permanent river in Mauritania, and its flood plain provides the country with all its water for agriculture. Vegetation in this area is semi-tropical.
The coastal region of Mauritania is humid but temperate thanks to the trade winds it receives from the Canary Islands. The coast is also characterized by sand dunes, with some marshy areas.