Origin Notes and History:
Chilliwack Lake adopted in the 15th Report of the Geographic Board of Canada, 31 March 1917, as labelled on BC Lands' map 2B, 1914, not "Chilukweyuk" as spelled on Trutch's 1871 map of British Columbia. See Chilliwack River & Chilliwack (city) for origin information.
Source: BC place name cards, or correspondence to/from BC's Chief Geographer or BC Geographical Names Office
The Halq'eméylem name for Chilliwack Lake is Sxótsaqel, meaning "sacred lake; something that is sacred" (from Halq'eméylem Place Names, by Naxaxalhts'i, Albert (Sonny) McHalsie. Stó:lo Nation, March 2012)
Source: included with note