The Duluth and Iron Range Railway Company was incorporated on December 21, 1874. The first main line from Two Harbors to Soudan, Minnesota, a distance of 68 miles, was completed in July 1884, and the first iron ore shipments arrived at Two Harbors on July 31, 1884. This ore was handled on a wooden dock which had been partially completed by that date. Four other wooden docks were subsequently built. Dock No. 6, which was built in 1907-08, was the first steel dock in the United States. Two steel and concrete docks later replaced the wooden docks.

In 1886, a spur was built from Tower Junction to Tower, MN, and a line was completed between Two Harbors and Duluth. In 1888, a line was built between Tower and Ely; and in 1893, a branch was built to Biwabik, Eveleth and Virginia. The Eastern Mesaba Branch was completed in 1910 and an extension to Burntside Lake in 1913. A branch from Wales to Whyte was completed in 1917, and this line was extended from Whyte to Forest Center in 1948.

The Duluth Missabe and Northern Railway Company was incorporated on February 11, 1891. Construction of the railroad from Mountain Iron to Stony Brook Junction on the former Duluth and Winnipeg Railway- a distance of 48 miles -was completed in October of 1892. The first shipment of iron ore was made late in October of 1892 from Mountain Iron, and moved over the Duluth and Winnipeg Railroad to Lake Superior. In the fall of that same year, the Biwabik Branch from Iron Junction to Biwabik- distance of about 16.5 miles- was completed, and in the spring of the following year a five mile line from Wolf to Virginia was opened to traffic.

The railroad built a line from Columbia Junction, near Stony Brook Junction, starting in the winter of 1893, and the first ore dock at Duluth was built in the same year. From that time, ore moved on the DM&N all the way from the mines to the docks at Duluth. Also in that year, the Superior Branch from Wolf to Hibbing- about 16 miles in length – was completed, and a branch to Eveleth was built in 1895.

In 1937, the Spirit Lake Transfer Railway was consolidated with the Duluth Missabe & Northern Railway Company to become the Duluth, Missabe, and Iron Range Railway Company with ownership under U.S. Steel. In 1938, the Duluth, Missabe and Iron Range Railway Company acquired the Duluth and Iron Range Railroad Company and the Interstate Railroad Company.

In 2001, the Duluth, Missabe and Iron Range Railway Company became part of Great Lakes Transportation. Great Lakes Transportation is a privately-held transportation holding company with principal operations in railroad freight and transportation, Great Lakes shipping, and inland river barging. The Great Lakes Transportation subsidiary companies were formed over the years to meet the transportation needs of various steel making facilities that were the predecessors of today’s United States Steel Corporation’s U.S. Steel Group. Prior to 1988, the Great Lakes Transportation companies were wholly owned transportation subsidiaries of United States Steel Corporation. In December, 1988, these transportation companies were acquired by a holding company, Transtar, Inc., which was the predecessor of Great Lakes Transportation.

In 1988, U.S. Steel, now USX, spun off the DM&IR and their other ore railroads and shipping companies into the subsidiary Transtar, then sold majority control to the Blackstone Group and USX. In 2001, the DM&IR and other holdings were spun off from Transtar into the company Great Lakes Transportation (GLT) which was fully owned by the Blackstone Group. For the first time in over 100 years DM&IR was no longer associated with U.S. Steel. In late 2003, the Blackstone Group agreed to sell GLT to Canadian National Railway and the purchase was finalized on May 10, 2004.

In December 2011, the Duluth, Missabe & Iron Range Railway was merged into Wisconsin Central Ltd., which is also controlled by Canadian National Railway. This merger was intended to increase efficiency.