National Road | ||||
Route information | ||||
Maintained by IDOT | ||||
Length | 159.8 mi[1][2] (257.2 km) | |||
Existed | 1926 | –present|||
Tourist routes | Historic National Road | |||
Major junctions | ||||
West end | I-55 / I-64 / US 40 in East St. Louis | |||
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East end | I-70 / US 40 near State Line, IN | |||
Location | ||||
Country | United States | |||
State | Illinois | |||
Counties | St. Clair, Madison, Bond, Fayette, Effingham, Cumberland, Clark | |||
Highway system | ||||
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U.S. Route 40 (US 40) runs east–west across south central Illinois for 159.8 miles (257.2 km). US 40 enters the state from Missouri across the Poplar Street Bridge over the Mississippi River at East St. Louis concurrent with Interstate 55 (I-55) and I-64 and exits just south of State Line, Indiana, running concurrently with I-70. For the majority of its route through Illinois, US 40 follows the National Road, including the route's initial western terminus at Vandalia.
For nearly its entire route, US 40 is two-lane and rural, with the exception of portions in and around major towns and cities. For its entire length, US 40 closely aligns with I-70. Not only does the route intersect with the Interstate six times, but also has three concurrencies with the highway; both highways exit into Indiana on the same road.