Michigan (Steamboat), 2 May 1871

      Opening of Navigation to Lake Superior for Fifteen Years. -- As matter for future reference we present below the date of opening of navigation to Lake Superior for fifteen successive years, including the present, the date of which we set down as May 10th, and so far as ice encumbrances are concerned, the Sault River throughout its length has been clear for the past several days.
      1855 - June 18, steamer ILLINOIS, 927 tons, first boat through.
      1856 - May 4, steamer MANHATTAN, 320 tons, first boat through.
      1857 - May 9, steamer NORTH STAR, 1,100 tons, first boat through.
      1858 - April 18, prop IRON CITY, 600 tons, first boat through.
      1859 - May 3, steamer LADY ELGIN, 1,038 tons, first boat through.
      1860 - May 11, propeller FOUNTAIN CITY, 920 tons, first boat through.
      1861 - May 3, steamer MICHIGAN, 642 tons, first boat through.
      1862 - April 27, steamer CITY OF CLEVELAND, 788 tons, first boat through.
      1863 - April 28, propeller MINERAL STATE, 555 tons, first boat through.
      1864 - May 5, propeller DUBUQUE, 384 tons, first boat through.
      1865 - May 3, propeller LAC LA BELLE, 857 tons, first boat through.
      1866 - May 7, propeller NORTHERN LIGHT, 716 tons, first boat through.
      1867 - May 6, steamer KEEWEENAW (sic), 634 tons, first boat through.
      1868 - May 4, steamer KEWEENAW, 634 tons, first boat through.
      1869 - May 7, propeller ST. PAUL, 900 tons, first boat through.
      1870 - April 25, propeller PACIFIC, 616 tons, first boat through.
      1871 - May 10, steamer KEWEENAW leaves Detroit, first boat.
      Detroit Free Press
      May 2, 1871