Did You Know? Louisiana is bordered to the west by the state of Texas; to the north by Arkansas; to the east by the state of Mississippi; and to the south by the Gulf of Mexico. The surface of the state may properly be divided into two parts, the uplands and the alluvial, including coast and swamp regions. The alluvial regions, including the low swamps and coast lands, cover an area of about 20,000 square miles (52,000 km˛). They lie principally along the Mississippi River, which traverses the state from north to south for a distance of about 600 miles (1,000 km) and empties into the Gulf of Mexico; the Red River; the Ouachita River and its branches; and other minor streams (some of which are called bayous). The breadth of the alluvial region along the Mississippi is from 10 to 60 miles (15 to 100 km), and along the other rivers the alluvial region averages about 10 miles (15 km) across. The Mississippi River flows along a ridge formed by its own deposits (known as a levee), from which the lands decline toward the low swamps beyond at an average fall of six feet per mile (3 m/km). The alluvial lands along other streams present similar features. Some Louisiana urban environments have a multicultural, multilingual heritage, so strongly influenced by an admixture of 18th century French, Spanish and African cultures that they are something exceptional in the U.S. Before the American influx and statehood at the beginning of the 19th century, the territory of current Louisiana State had been a Spanish and French colony. In addition, the pattern of development included importing numerous Africans in the 18th century, with many from the same region of West Africa, thus concentrating their culture. Also, thousands of refugees arrived from Saint-Domingue in the early 1800s, many bringing slaves with them, also adding a strong new African influence on the culture, especially of southern Louisiana in and near New Orleans.