Origin Notes and History:
Adopted 13 March 1947 on C.3688, as labelled on British Admiralty Chart #1917, 1863 et seq. Confirmed 6 November 1952 on 102I.
Source: BC place name cards, or correspondence to/from BC's Chief Geographer or BC Geographical Names Office
"Thus named on Admiralty chart of 1849, the island with the reefs around it being shown on that chart in the shape of a triangle."
Source: Walbran, John T; British Columbia Coast Names, 1592-1906: their origin and history; Ottawa, 1909 (republished for the Vancouver Public Library by J.J. Douglas Ltd, Vancouver, 1971)