[4] The lake is named in honour of Duncan Archibald McArthur, a private soldier who died on 28 August 1944 during the Allied invasion of Normandy.

[4] Geologically the area is in the Precambrian Kisseynew complex, underlain by an assemblage of metamorphosed sedimentary rocks that has been intricately folded, with intrusions of sill-like granitic bodies.

[8] There are a number of northerly plunging folds between McArthur and Kakinagimak lakes with axial planes 20° NE, dipping sharply to the east.

[4] There are small patches of moss-covered muskeg that support laurel (kalmia microphylla), labrador tea, and scattered larch and black spruce.

[13] Animals hunted for meat or fur include moose, woodland caribou, black bear, beaver, otter and muskrat.

[13] Dark grey to black garnet-hornblende gneiss is exposed in an area from north of Bentz Bay to just south of McArthur Lake.