(chēä'päs), state (1990 pop. 3,210,496), 28,732 sq mi (74,416 sq km), SE Mexico, on the Pacific Ocean between Guatemala and the Isthmus of Tehuantepec. Tuxtla Gutiérrez is the capital. Chiapas is crossed by mountain ranges rising from the isthmus and extending southeast into Guatemala. They are separated by low, subtropical valleys. Paralleling the coastal plain is the Sierra Madre de Chiapas, reaching 13,310 ft (4,057 m) at Tacaná volcano. The state's principal river valley is the Grijalva, northeast of which are the central highlands. Farther to the northeast are lower ranges, lakes, and valleys, falling away toward the Usumacinta River and the rain-forested plains of Tabasco . This sparsely inhabited region contains valuable but dwindling forests of dyewoods and hardwoods and is also the site of ruined Mayan cities (notably Palenque ). The area is also the retreat of the Lacandones, a gradually disappearing indigenous people often thought to be related to the ancient Maya. The…