KOKO-NOR (or Kuku-Nor) (Tsing-hai of the Chinese, and Tso-ngombo of the Tanguts), a lake of Central Asia, situated at an altitude of 9975 ft., in the extreme N.E. of Tibet, 30 m. from the W. frontier of the Chinese province of Kan-suh, in 100° E. and 37° N. It lies amongst the eastern ranges of the Kuen-lun, having the Nan-shan Mountains to the north, and the southern Koko-nor range (10,000 ft.) on the south. It measures 66 m. by 40 m., and contains half a dozen islands, on one of which is a Buddhist (i.e. Lamaist) monastery, to which pilgrims resort. The water is salt, though an abundance of fish live in it, and it often remains frozen for three months together in winter. The surface is at times subject to considerable variations of level. The lake is entered on the west by the river Buhain-gol. The nomads who dwell round its shores are Tanguts.