San Luis Potosí (sän lōēsˈ pōtōsēˈ) [key], state (1990 pop. 2,003,187), 24,417 sq mi (63,240 sq km), central Mexico. San Luis Potosí is the capital. Most of the state lies on the eastern tablelands of Mexico's central plateau. Except in the humid tropical Pánuco River valley in the extreme east, near the Gulf of Mexico, the climate is mild and dry. Generally level, with an average elevation of 6,000 ft (1,829 m), the plateau is broken by spurs of the Sierra Madre Oriental; it is largely desert in the north. Rainfall is generally light, and rivers are few; thus, despite fertile soil, agriculture is practiced mainly for subsistence. Large crops of sugarcane, however, are cultivated in the eastern lowlands. Some timber is cut, but the state's tropical forests remain mostly unexploited. San Luis Potosí has rich silver, gold, copper, zinc, and bismuth deposits and is one of Mexico's leading mining states. Industry is limited, yet diverse; basic metal manufacturing comprises the largest sector.