Tŝilhqox Biny (Pronounced: Tsyle-koh Bee), known as Chilko Lake, is a 180 km2 lake in west-central British Columbia, at the head of the Chilko River on the Chilcotin Plateau. The lake is about 65 km long, with a southwest arm 10 km long. It is one of the largest lakes by volume in the province because of its great depth, and the largest above 1,000 m in elevation. It and Harrison Lake are the largest lakes in the southern Coast Mountains. On March 11, 2019, the Province of British Columbia, working with the Tŝilhqot’in National Government, officially changed the name of the lake from Chilko Lake to Tŝilhqox Biny. Geography The inland equivalent of the many fjords which line the British Columbia Coast on the other side of the Coast Mountains, Tŝilhqox Biny's glacial valley opens not out onto the ocean, but onto a broad lava plateau that lies inland from the highest section of the main range. The mountains at the head of the lake are among the highest in the province, and two broad, deep glacial valleys connect east to the smaller Taseko Lakes, which drains northwards parallel to the Chilko River, both of them converging with the Chilcotin River which is a tributary of the Fraser. Tatlayoko Lake, to the west across another range, is not part of the Chilcotin-Fraser drainage, however, but is part of the Homathko River drainage to Bute Inlet. The area spanning the head of Tŝilhqox Biny and Taseko Lake basins and the two valleys between the two lakes has been preserved as the Tsʼilʔos Provincial Park, which is co-administered by the Parks Branch of the provincial government and by the Xeni Gwet'in, who are the residents of Nemaia Valley and one of the component bands of the Tsilhqot'in (Chilcotin) people; Nemaia is the more northerly of the two east–west valleys, the southerly one is Yohetta Valley. Tsi'l?os is the Tsilhqot'in name for Mount Tatlow 3,063 m (10,049 ft), which stands in the ranges between Chilko and Taseko Lakes. Higher still are the mountains at the head of Tŝilhqox Biny, crowned by 3,182 m (10,440 ft) Monmouth Mountain, and to the southwest of the lake, between the two arms, is Mount Good Hope 3,242 m (10,636 ft), with the range rising west from there towards Mount Queen Bess 3,298 m (10,820 ft), to the south of Tatlayoko Lake and higher still beyond to