I-39

About I-39

From Normal, IL (I-55) to Wausau, WI (US 51)

Interstate 39 is a north-south route of about 304 miles running from the Bloomington-Normal area of central Illinois north into Wisconsin, ending near Wausau. It crosses Illinois and Wisconsin, much of it concurrent with other Interstates, and serves as a connector through the interior of the upper Midwest. The route links central Illinois with central Wisconsin through Rockford and Madison.

From its southern terminus at I-55 near Normal, Illinois, the route runs north through La Salle-Peru and Rockford, then enters Wisconsin and shares a long concurrency with I-90 and I-94 toward Madison. North of Madison it continues alone through Portage and Stevens Point before ending near Wausau. Much of its mileage overlaps with I-90 and I-94 in the concurrent section.

State-by-state mileage

State	Miles
Illinois	140.8
Wisconsin	165.3
Total	306.1

History

I-39 was designated in the mid-1980s, later than most mainline Interstates, and built largely by upgrading existing US 51 and connecting corridors to Interstate standards. The number filled in a north-south route through the interior of Illinois and Wisconsin that the original plan had not included.

Major cities and places

Did you know

• Designated in 1986, later than most mainline Interstates.
• Shares a long concurrency with I-90 and I-94 in Wisconsin.
• Built largely by upgrading the US 51 corridor.
• Crosses only Illinois and Wisconsin.