Number of Miles 349 Illinois - 139 miles Wisconsin - 210 miles Major Cities Along the Route Normal, Illinois Madison, Wisconsin Intersections with other Interstates Interstate 55 in Normal, Illinois Interstate 80 in La Salle, Illinois The western Interstate 88 in Rochelle, Illinois Interstate 90 in Rockford, Illinois. They stay joined until Portage, Wisconsin Interstate 43 in Beloit, Wisconsin Interstate 94 in Madison, Wisconsin. They stay joined for 30 miles. Spur Routes None Notes Future plans call for Interstate 39 to be extended north from Wausau to Merrill, Wisconsin along the United States Highway 51 freeway, which is Interstate standard, but it is not signed as Interstate as of December 2001.
Notes Future plans call for Interstate 39 to be extended north from Wausau to Merrill, Wisconsin along the United States Highway 51 freeway, which is Interstate standard, but it is not signed as Interstate as of December 2001.