Durango (pronounce [duˈɾaŋgo]) is one of the constituent states of Mexico. Its population of the 2005 census was approximately 1,509,117 people. It has Mexico's second-lowest population density (after Baja California Sur). The city of Durango is the state's capital. Most of the state is heavily mountainous and a good part forested, the Sierra Madre Occidental occupies the western and central part of the state. This mountain range contains a good supply of minerals, including the silver that encouraged Spanish occupation of the territory after it was discovered. These mines extend north into Chihuahua and south into the state of Zacatecas. Vast desert basins in the Laguna District are irrigated by the Nazas River. Major crops grown in the area include cotton, wheat, corn, alfalfa, beans, sorghum and other vegetables.