Yahk River adopted in the 18th Report of the Geographic Board of Canada, 31 March 1924. Spelled "Yaak River" in the U.S. Length in BC = approximately 27.7 km.
Source: BC place name cards, or correspondence to/from BC's Chief Geographer or BC Geographical Names Office
"Yahk" is the Kootenay Indian name of the river (variously spelled Yaak, Yak and Yaht), meaning "arrow", referring to its arrow-like position at the bow or bend of the Kootenay River.
Source: Provincial Archives of BC "Place Names File" compiled 1945-1950 by A.G. Harvey from various sources, with subsequent additions
From the Indian word "yaak" meaning "bow", a name which the Kootenay Indians applied to the Kootenay River which first flows south then west, then north. By extension the word would be applied to the country contained within the "bow" of the Kootenay River. Some derive the name from "a'k" meaning "arrow".
Source: Akrigg, Helen B. and Akrigg, G.P.V; 1001 British Columbia Place Names; Discovery Press, Vancouver 1969, 1970, 1973.