Interstate 70 in Illinois - Route Description

Route Description

I-70 enters Illinois from St. Louis by crossing the Mississippi River on the eight-lane Poplar Street Bridge into the city of East St. Louis in St. Clair County. I-70 runs concurrently with I-55, I-64, and US 40 entering the state. At the east end of the bridge, the Interstate splits into express and local lanes, both with two lanes each direction, as it passes through a pair of directional interchanges. The first interchange is for IL 3, which heads south toward Cahokia, and the second is for Tudor Avenue and Piggott Avenue, which form a one-way pair in a residential area of East St. Louis. The east end of the interchange complex has an eastbound exit to Fourth Street and a westbound entrance from Main Street. IL 3 joins the highway to form a five-way concurrency, which reduces from eight to six lanes. The Interstate curves around downtown East St. Louis and has two partial interchanges, both with westbound exit and eastbound entrance, for the Martin Luther King Bridge and Eads Bridge toward Downtown St. Louis; both roadways temporarily expand to five lanes. I-64 and IL 3 (St. Clair Avenue) leave the concurrency at the next interchange, taking two lanes from each direction. I-70 and I-55 have a westbound exit to and eastbound entrance from Exchange Street before the Interstate leaves the city of East St. Louis by crossing over the main east–west railroad line.

I-70 and I-55 have an interchange with IL 203 before entering Madison County. The Interstate has a diamond interchange with IL 111 just north of Fairmont City and a partial interchange with Black Lane before the highway's interchange with I-255 west of Collinsville. I-70 and I-55 curve northeast around Collinsville and leave the floodplain of the Mississippi River at the interchange with IL 157 (Bluff Road), where the highway reduces to four lanes. The Interstate passes between Collinsville and Maryville, which are both served by the next interchange with IL 159 (Vandalia Street/Maryville Road). US 40 leaves the freeway at a trumpet interchange southwest of Troy. I-70 and I-55 curve to the north and meet IL 162 (Edwardsville Road) before I-70 and I-55 diverge at the highways' interchange with I-270. The interchange, Exit 20, is a full cloverleaf except for a flyover ramp for westbound I-70 to join southbound I-55. Westbound I-70's interchange number is Exit 15, marking the continuation of I-270's number sequence that I-70 will carry east to Indiana.

I-70 meets IL 4 and IL 143 to the south and east of Marine before crossing Highland Silver Lake. US 40 joins I-70 again near Pierron, Illinois and run concurrently into Bond County, where the highways separate at Pocahontas, where I-70 crosses Shoal Creek. US 40 continues to closely parallel I-70 until the next interchange, which is a connector to US 40 southwest of Greenville. The two highways pass to the south of Greenville, which is also served via an interchange with IL 127. East of Mulberry Grove, I-70 and US 40 cross to the north side of the east–west rail line and again closely parallel each other into Fayette County. I-70 passes along the northern edge of Vandalia, with access to the county seat of Fayette County provided by an interchange with US 40 on the west side and US 51 (Kennedy Boulevard) to the north. Just east of US 51, I-70 crosses the Kaskaskia River. I-70 crosses to the south side of both the rail line and US 40 (Cumberland Road) between Bluff City and Brownstown. The Interstate passes to the south of St. Elmo before entering Effingham County to the west of an interchange with IL 128 at Altamont.

Immediately after crossing the Little Wabash River, I-70 joins I-57 in a concurrency to pass around the west and north sides of Effingham. The two Interstates use I-57's exit sequence during the overlap. I-70 and I-57 intersect Fayette Avenue, IL 32 and IL 33 (Keller Drive), and US 45 (Third Street) before diverging near Teutopolis. Just east of Montrose, I-70 enters Cumberland County, where the Interstate has one interchange with IL 130 (Haughton Highway) at Greenup, where the highway crosses the Embarras River. The Interstate continues into Clark County for an interchange with IL 49 north of Casey. I-70 crosses the North Fork Embarras River north of Martinsville, then has a junction with IL 1 north of the county seat of Marshall. Northeast of Marshall, US 40 joins I-70 in a concurrency. The Interstate and U.S. highway cross the Indiana state line west of Terre Haute while closely paralleling the original alignment of US 40, Illiana Drive.