Adopted 1936 February 11 on Map #93G/3, as established on British Admiralty Chart #1922, 1827, and Canadian Hydrogrpahic Chart #330, date not cited.

Source: BC place name cards & correspondence, and/or research by BC Chief Geographer & Geographical Names Office staff.

It has been suggested by Westham residents that this name derives from the island’s westerly location in the delta of the Fraser River. A more likely explanation, however, is that it is named after West Ham in Essex, now part of greater London, which was the original home of early settler Harry Trim, who had a varied career as a fisherman, whaler and prospector. Henry Mitchell was one of the first to farm on the island, in the 1870s. The Westham landscape is still completely agricultural, through the NW part of the island is now also an important bird refuge, home of the Alaksen National Wildlife Area and the George C Reifel Migratory Bird Sanctuary, which occupies neighbouring Reifel Island as well.

Source: Scott, Andrew; "The Encyclopedia of Raincoast Place Names"; Harbour Publishing, Madeira Park, 2009, page 639.

R.E. Gosnell, writing in 1897, said that the island was named after a village in Essex, England. However, H.W. Rich who lived on the island in 1880 declared that it got its name 'as it is the most western point on the mainland South of the Fraser River.'

Source: Akrigg, Helen B. and Akrigg, G.P.V; "1001 British Columbia Place Names"; Discovery Press, Vancouver 1969, 1970, 1973.