There is a toll plaza just south of Rockton Road. While concurrent, I-39/I-90 follows I-90's exit numbering. I-39 then runs east concurrently with US 20 to where the Interstate joins the Jane Addams Memorial Tollway and I-90 near Cherry Valley. Further north, I-39 crosses the Kishwaukee River before meeting US 20 on the southside of Rockford. I-39 intersects I-88 at exit 97 in Rochelle. North of I-80, the wind turbines of the Mendota Hills Wind Farm can be seen from milepost 72 at Mendota north to near Paw Paw. Just north of the Illinois River, I-39 runs east of the cities of LaSalle and Peru before intersecting I-80 at exit 59. About 55 miles (89 km) north of the city, I-39 crosses the Illinois River over the Abraham Lincoln Memorial Bridge, which is 1.3 miles (2.1 km) long. From the city, I-39 runs north largely through rural areas, intersecting Illinois Route 251 (IL 251) at exit 8. I-39's southern terminus is less than one mile (1.6 km) from I-74 as I-74 runs around the city of Normal. In Illinois, I-39 begins at I-55, north of the Bloomington–Normal, Illinois. From Portage northward, US 51 is cosigned with the Interstate and has exit numbers based on its mileage.Īerial view of I-39 as it passes Minonk, Illinois, April 2012 At 29 miles (47 km) in length, this concurrency of three Interstates is the longest in the country. In Wisconsin, I-94 joins the pair in Madison until Portage. From Rockford, Illinois, to Portage, Wisconsin, I-39 runs concurrently with I-90. With the exception of an eight-mile (13 km) segment around Portage, Wisconsin, the Interstate shares a route with at least one other route number in I-39's entirety. In Wisconsin, I-39 has a distance of 182 miles (293 km). In Illinois, the route has a total length of 140.82 miles (226.63 km).

Route 51 (US 51), which, in the early 1980s, was one of the busiest two-lane highways in the United States. I-39 runs from Normal, Illinois, at I-55 to State Trunk Highway 29 (WIS 29) in the town of Rib Mountain, Wisconsin, which is approximately six miles (9.7 km) south of Wausau. Interstate 39 ( I-39) is a highway in the Midwestern United States. WI: Rock, Dane, Columbia, Marquette, Waushara, Portage, Marathon IL: McLean, Woodford, Marshall, LaSalle, Lee, Ogle, Winnebago

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