CHIAPAS HIGHLANDS

high-altitude region of dissected plateaus enclosing a central valley (Valle Central de Chiapas) in Chiapas state, southeastern Mexico. The highlands constitute the northwestern end of a mountainous region extending northward from the lowlands of Nicaragua to the Isthmus of Tehauntepec and are composed of three main features running parallel to the Pacific Ocean. The western section of the highlands is the Chiapas Sierra Madres, a crystalline range of mountains reaching elevations of 9,000 feet (2,700 m) within 20 miles (32 km) of the ocean. The Valle Central de Chiapas farther inland constitutes the central section. The Northern Mountains of Chiapas, block mountains capped with volcanic materials and reaching elevations above 12,000 feet (3,650 m), compose the eastern section. The Tacan volcanic cone, located on the southern extreme of the highlands at the Mexico-Guatemala border, rises to 13,484 feet (4,110 m). Rainfall is heaviest along the coastal slopes of the Chiapas Sierra Madres, where the Aztec peoples historically grew their supply of cacao. The Spaniards entered the region in 1524 and succeeded in dominating the Aztecs only after bitter fighting. Cacao is still produced on the coastal slopes, together with coffee at higher elevations. The central valley floor, drained by the Grijalva River, supports crops of corn (maize), bananas, and coffee; higher parts of the valley produce wheat, and, above the tree line in the northeastern mountains, there is a zone devoted to cattle grazing. Tuxtla, located at the northern end of the Grijalva valley, is the largest population centre of the region. Chicoasn, a major hydroelectric project, is situated about 12 miles (19 km) north of Tuxtla on the Grijalva River. The extraction of oil from the eastern side of the highlands increased greatly in economic importance in the late 1970s. An inter-American railway and a paved highway run along the base of the Chiapas Sierra Madres, and the Pan-American Highway extends through the central Chiapas valley to the Guatemala border.