Duffey Lake adopted in the 18th Report of the Geographic Board of Canada, 31 March 1924, as labelled on a map of British Columbia drawn by the Royal Engineers in September 1863 (Royal Geographical Society call no. D.52) and on Trutch's 1871 map of British Columbia, etc.

Source: BC place name cards, or correspondence to/from BC's Chief Geographer or BC Geographical Names Office

Approved 26 June 1911 on Ottawa file OBF 0024. "Named after a miner by the name of Patrick Duffey, of Lillooet." (1 April 1911 letter from Provincial Minerologist to Geographic Board of Canada (Ottawa file 92J, Volume 11), reprinted in the 18th Report.

Source: Canadian Geographical Names Database, Ottawa

Geographic Board says "after Patrick Duffey, miner, Lillooet." However, a more likely origin is William Duffy, who explored this valley while seeking a route from Cayoosh (Lillooet) to Lillooet Lake in September 1860.

Source: Provincial Archives' Place Names File (the "Harvey File") compiled 1945-1950 by A.G. Harvey from various sources, with subsequent additions

Named by the Royal Engineers in September 1863, after Sapper James Duffy, RE, ( -1861), who in 1860 explored and surveyed the route to Lillooet via Cayoosh Creek, as part of the proposed Harrison Lake-Lillooet route to the Cariboo goldfields.

Source: BC place name cards, or correspondence to/from BC's Chief Geographer or BC Geographical Names Office

"On his one mile to one inch strip map (PABC Call No. 8500 A61), Duffy names the long lake between his camps 4 and 5 as Lake Melvin. We do not know whom Duffy was honouring, and the lake was actually named "L Duffey" on the map of British Columbia completed...[September 1863]... by his colleagues in New Westminster. (Duffy's "Lake Melvin" was accomodated by a later Surveyor General who named a small lake Melvin Lake...about 5 miles east of Duffey Lake). We have not traced Duffy's movements for the remainder of 1860, but he was back on the Harrison-Lillooet trail early in 1861. The British Colonist reported 18 January 1861 that he had been found frozen to death in the snow on the first, or long portage between the head of Harrison Lake and Lillooet Lake. With some difficulty his body was returned to New Westminster, where he was escorted to his grave by the whole detachment of Royal Engineers on Sunday 19 January 1861. Duffy's name has been recorded 3 ways: Governor Douglas used "Duffie" in his diary (Despatch #13, 9 October 1860, Douglas to Newcastle, Colonial Secretary in London); Royal Army records in England show "James Duffy" enlisted 2 October 1848 and was assigned Regimental Number 2146 - his was the only death in the Columbia Detachment in 1861, recorded as 9 January; Duffy and his colleagues used [the spellings] Duffy and Duffey almost indiscriminately - there was a slight preference for "Duffy", though it is recorded "Lake Duffey" on the last RE map of British Columbia. The Geographic Board of Canada has adopted "Duffey", possibly to distinguish it from the Duffy Creek and Lake south of Kamloops..." (R.C. Harris, "Sapper Duffy's Exploration Cayoosh Creek to Lilloett Lake, 1860", printed in British Columbia Historical News, Vol 14, No.2; copy received February 1981, file P.1.65 #2).

Source: included with note