The Chihuahuan Desert is a desert and ecoregion designation covering parts of Mexico and the United States. It occupies much of West Texas and small parts of New Mexico, and Arizona, as well as the central and northern portions of the Mexican Plateau. It is bordered on the west by the extensive Sierra Madre Occidental range, along with northern portions of the Sierra Madre Oriental range. On the Mexican side, it covers the northern half of the state of Chihuahua, along with the majority of Coahuila, north-eastern Durango, the extreme northern part of Zacatecas, and small western portions of Nuevo León. With an area of about 362,000 km2 (139,769 sq mi), it is the third largest desert of the Western Hemisphere and the second largest in North America, after the Great Basin Desert.