In September 1883 a consortium of flour mill owners in Minneapolis formed the Minneapolis, Sault Ste. Marie and Atlantic Railway to build a railroad between Minneapolis and Sault Ste. Marie to bypass Chicago. By 1888 the Canadian Pacific acquired control of the railroad and combined it with two other railroads to create the Minneapolis, St. Paul, and Sault Ste. Marie Railway.
The line took the name Soo Line because of the common pronunciation of the French word Sault.