Mauritania (môrĭtā`nēə), officially Islamic Republic of Mauritania, republic (2015 est. pop. 4,182,000), 397,953 sq mi (1,030,700 sq km), NW Africa.It borders on the Atlantic Ocean in the west, on Western Sahara in the northwest and north, on Algeria in the northeast, on Mali in the east and southeast, and on Senegal in the southwest.

