, 1863 , 1954) The British Indian explorers in the 19th century knew the lake as
Tso Rul ("Bitter Lake") and stated that its waters were extremely bitter. The lake lies in a long valley that connects the Chushul Valley to the Rudok Valley. A single river, Tangre Chu, flows along the valley for 10–12 miles, and drains into the Spanggur Tso. The lake is about long and less than wide.
Henry Strachey found fossil shells of
Lymnaea auricularia along its shores, leading to the conclusion that the waters of the lake must have been at one time fresh. To the west of the lake, there is a gap in the mountains, which is referred to as the
Spanggur Gap. The mountains to the north of the gap are thought to belong to the
Pangong Range, while those on the south are regarded part of the
Kailash Range. The Spanggur Gap connects Spanggur area to the Chushul Valley (or Tsaka Chu valley) running north–south on the Ladakh side of the border. At one time the Spanggur Tso must have drained through the gap into the Tsaka Chu Valley and Pangong Tso. The present state of affairs is believed to be either due to subsidence of the Spanggur Valley. The British Boundary Commission for Kashmir in 1847 placed the entire Spanggur lake in Tibet's
Rudok Dzong (modern
Rutog County). (Map 1) The Kashmir Survey, completed in 1864, placed slightly more than half the lake in Ladakh but the eastern extremity in Rudok. (Map 2) == Chinese administration ==