 The laws setting up the construction of the Military Road established a five @-@ year deadline for construction . The war removed laborers in mining , lumbering and shipping as well as soldiers from the available workforce , and Congress extended the deadline an additional 21 months in June 1868 . A second extension was granted in May 1870 . The Wisconsin section of the highway was completed on June 20 , 1870 . The Houghton County segment was finished in January 1871 . The Keweenaw County section was completed by August 1871 . A third and final extension on the deadline was needed in April 1872 , and the roadway was completed south to the state line in September 1873 , shifting the southern segment in the Upper Peninsula west to the modern US 45 corridor in place of the FFH @-@ 16 alignment . 
