 The northernmost section of the modern US 41 between Houghton and Copper Harbor originated in the 19th century as the Military Road . The road was one of 13 roads built between 1817 and 1864 by the federal government . Construction of the road was proposed as early as two years after the US acquired the last tracts of land in the Upper Peninsula . Congress asked Secretary of War William Wilkins for funding to build such a road in 1844 , since the area depended on a land connection to Green Bay , Wisconsin , for up to six months a year for supplies and mail . The estimate for a 220 @-@ mile @-@ long ( 350 km ) , 33 @-@ foot @-@ wide ( 10 m ) crude road was $ 37 @,@ 400 ( equivalent to $ 21 @.@ 8 million in 2015 ) . The matter died until 1848 when the Michigan Legislature petitioned Congress for an appropriation to build to connect Green Bay to the Keweenaw Bay . The appeal went unfulfilled by the government , but private groups stepped in . Mail service was available overland once a month during the winter from Green Bay . In 1857 , the Legislature enacted a law to provide a road from Eagle Harbor south to Ontonagon . This road was extended south to the state line pursuant to two laws in 1859 . 
