mountain group, eastern Taiwan. It trends north-south and consists of three main ranges (respectively, from east to west): the Chung-yang Range, Yü Mountains, and A-li Mountains. The Chung-yang Range traverses the length of the island, extending about 170 miles (270 km) in length and up to 50 miles (80 km) in width, with some 27 peaks rising above 9,850 feet (3,000 m). Mount Yü (also called Mount Hsin-kao, formerly Mount Morrison) is the highest peak in the range and in Taiwan, at 13,114 feet (3,997 m).

The range is composed mainly of schists, quartzites, and gneisses and is terminated very abruptly by the T'ai-tung rift valley on the east and more gradually by a hilly region leading down to Taiwan's fertile coastal plain on the west. Much of the A-li range is faulted, giving rise to structural depressions, in one of which lies Jih-yüeh (“Sun Moon”) Lake, site of a major hydroelectric plant. Rainfall on the mountain slopes is abundant, usually exceeding 150 inches (3,800 mm), and the range gives rise to the Cho-shui, Ta-chia, Kao-p'ing, and Hsin-Wu-lü rivers. Forests of broad-leaved trees predominate at lower elevations, giving place to mixed forests at higher elevations and finally, above 6,000–8,000 feet (1,800–2,400 m), to coniferous forests. The region is sparsely settled except for scattered groups of aborigines.