1910  (1921)  The . . . khaki pants, brown leather shoe packs, and short Mackinaw coat contrasted with the elaborate tourist gear that his companion had evidently acquired of a London outfitter.
1935  The original mackinaw coats were made from Hudson's Bay "Point" blankets for the British soldiers who, during the war of 1812, fought in the neighbourhood of Mackinaw. Captain Charles Roberts was unable to obtain greatcoats for his men, so commandeered a supply of "Point" blankets and coats were designed and made by one of his men.
1956  Sure enough, a guard in plain clothes brought along my mackinaw jacket and hat and invited me to come along with him.