|Ulysses S. Grant Memorial Highway|
|Maintained by IDOT and CDOT|
|Length||233.93 mi  (376.47 km)|
|West end||US 20 in East Dubuque|
|East end||US 12 / US 20 / US 41 in Chicago|
|Counties||Jo Daviess, Stephenson, Winnebago, Boone, McHenry, Kane, DuPage, Cook|
U.S. Route 20 (US 20) in the U.S. state of Illinois is a major arterial highway that runs from the Iowa state line at East Dubuque at the northwestern tip of Illinois, to the Indiana state line at Chicago south of the Chicago Skyway, a distance of 233.93 miles (376.47 km).  For its entire length, US 20 is designated as the General Ulysses S. Grant Highway, often abbreviated the U.S. Grant Memorial Highway. However, this name is only commonly used west of Elgin. From Elgin to Melrose Park, US 20 follows Lake Street. It then follows Mannheim Road, and further south La Grange Road. US 20 also follows 95th Street as it turns east through Chicago's southwestern suburbs. It ultimately leaves Illinois on Indianapolis Boulevard.
As the highway enters Illinois across the Julien Dubuque Bridge, it continues southeasterly for a while, paralleling the Upper Mississippi River before turning east into the rugged country of the Driftless Area in Jo Daviess County, then turning flat and straight west of Stockton, Illinois and entering Stephenson County. The Ulysses S. Grant Home, a national landmark, fronts near the highway at the eastern edge of Galena, Illinois.
The road between Dubuque and Stockton was once known as the most dangerous stretch of road because of the hills and curves flanked by cliffs and valleys. Travelers were greeted with signs reminding them to drive carefully as they entered this stretch of road.
In Freeport, US 20 is routed onto a limited-access freeway bypass. Between Freeport and Rockford there are two traffic light-controlled intersections. The Rockford bypass routes US 20 onto a full limited-access freeway; it remains this way until it overlaps Interstate 39 southeast of downtown Rockford. Interchanges on the Rockford Bypass include West State Street (Business US 20), South Meridian Road, Montague Road, South Main Street ( Illinois Route 2), 11th Street ( Illinois Route 251), and South Alpine Road.
East of Rockford, the routing of US 20 runs parallel with Interstate 90, with US 20 serving minor cities that are not accessible from the Jane Addams Memorial Tollway. It is a four-lane divided highway from I-39 to just east of Belvidere; for the rest of this segment, it is a winding, rural two-lane road.
US 20 travels through the downtowns of the small towns and unincorporated areas of Garden Prairie, Harmony and Starks, as well as the city of Marengo. At Starks, eastbound US 20 overlaps southbound Illinois Route 47 and westbound Illinois Route 72, forming a wrong-way concurrency. All three routes pass beneath a railroad viaduct before separating south of Starks.
Continuing east, US 20 travels through Pingree Grove before entering the Elgin area. Before entering Elgin, US 20 widens to a four lane limited-access freeway that bypasses Elgin. This road is known as the Elgin Bypass.
At the end of the Elgin bypass, US 20 takes on the name of Lake Street. US 20 has numerous high-volume intersections, including a grade-separated interchange with Illinois Route 59. In Hanover Park, an early-2000s reconstruction project widened lanes on the road and created a median for safer travel; east of Barrington Road / County Farm Road, the road briefly becomes six lanes for one mile (1.6 km) until the Elgin–O'Hare Expressway.
US 20 continues in an east-southeast direction through the town center of Bloomingdale and becomes six lanes at the Bloomingdale- Roselle border. It maintains six lanes through a very high traffic corridor to Interstate 290 and onwards to Illinois Route 53 before it returns to four lanes while serving downtown Addison, paralleling Interstate 290 to the north. Past Elmhurst, the road overlaps Interstate 290 for a mile.
US 20 continues through Stone Park and Melrose Park before turning south and joining U.S. Routes 12/ 45. At this point, US 20 becomes Mannheim Road, and later, La Grange Road, until it turns onto 95th Street eastbound with U.S. 12. This combination later joins with U.S. Route 41, where the three routes follow Ewing Avenue and Indianapolis Boulevard, which are the last portions of US 20 prior to its crossing the state line into Indiana.
The routing of US 20 has not changed since 1938. Prior to 1938, US 20 continued east on Lake Street east of Mannheim Road (US 12/US 45). It ran through downtown Chicago and exited Chicago south on what is now Torrence Avenue.  In 1955, the Illinois General Assembly designated the entire length of US 20 in Illinois the "U.S. Grant Memorial Highway". New signs were produced in late 2007 to reflect this designation along its entire length. 
Long-range plans call for US 20 to be upgraded to a full four-lane highway from Rockford to the Iowa border near Dubuque. The project dates back to the 1970s, when a major supplemental freeway system was proposed in Illinois. One of the routes, FAP 401, was a freeway that was to run across northwestern Illinois from Rockford to Dubuque.  Portions of the freeway were built in the form of bypasses around Rockford and Freeport, while a four-lane divided expressway was built between those two cities. In addition, a four lane divided expressway was constructed between Galena and East Dubuque.
A freeway between Freeport and Galena has been proposed. The new roadway would run from an interchange with IL 84, northwest of Galena, to an interchange on the west end of the previously constructed Freeport bypass.  However, funding is the biggest obstacle to constructing the roadway, estimated at over $1 billion.  Only the Galena bypass segment has received any funding beyond Phase I, and no segment has received any construction funding. 
This would complete the last remaining section of US 20 in northwestern Illinois not upgraded to four lanes. Upon the completion of this project and construction a new four lane bridge over the Mississippi River, US 20 will be a continuous four lane divided highway between Rockford and Interstate 35 in Iowa.
All exits are unnumbered.
US 20 west / Great River Road (National Route) north – Dubuque
|Continuation into Iowa|
|Iowa–Illinois state line ( Julien Dubuque Bridge)|
|Jo Daviess||East Dubuque||0.7||1.1||IL 35 north – Wisconsin||Interchange; southern terminus of IL 35; no eastbound entrance|
|Rawlins Township||11.2||18.0||IL 84 north – Hazel Green Wis.||Western end of IL 84 overlap|
IL 84 south / Great River Road (National Route) south (Washington Street) – Hanover, Savanna
|Eastern end of IL 84/Great River Road overlap|
|Stockton||41.7||67.1||IL 78 south (Main Street) – Mount Carroll||Western end of IL 78 overlap|
|42.9||69.0||IL 78 north – Warren||Eastern end of IL 78 overlap|
|Stephenson||Lena||50.8||81.8||IL 73 – Lena, Pearl City|
US 20 Bus. east – Freeport
|Western terminus of US 20 Bus.; west end of expressway|
|61.8||99.5||IL 26 – Freeport, Monroe Wis.|
|65.0||104.6||IL 75 – Freeport, Rockton|
|68.8||110.7||Springfield Road – Freeport||Eastbound exit and westbound entrance|
US 20 Bus. west – Freeport
|Westbound exit and eastbound entrance; eastern terminus of US 20 Bus.; east end of expressway|
US 20 Bus. east (State Street)
|Eastbound exit and westbound entrance; western terminus of US 20 Bus.; west end of freeway section|
|92.7||149.2||IL 2 (Main Street) – Dixon|
|94.6||152.2||IL 251 (11th Street) – Rochelle|
|97.3||156.6||I-39 / US 51 south – Bloomington||Western end of I-39/US 51 overlap|
I-39 north / US 51 north to I-90 (Jane Addams Memorial Tollway) / Harrison Avenue – Chicago, Wisconsin, Rockford
|Tolled; cloverleaf interchange; east end of freeway section; eastern end of I-39/US 51 overlap; I-39 exit 122A|
US 20 Bus. west (Belvidere Road) to I-90 (Genoa Road)
|Eastern terminus of US 20 Bus.|
|McHenry||Marengo||119.2||191.8||IL 23 (State Street) to IL 176 (Telegraph Street)|
I-90 (Jane Addams Memorial Tollway) – Chicago, Rockford
|Pingree Grove||133.6||215.0||IL 47 north / IL 72 east – West Dundee, Huntley||Western end of IL 47/IL 72 overlap|
|134.0||215.7||IL 47 south / IL 72 west – Elburn, Hampshire||Eastern end of IL 47/IL 72 overlap|
|Elgin||141.5||227.7||CR 34 ( Randall Road)||West end of Elgin Bypass freeway|
|141.6||227.9||Larkin Avenue||Eastbound exit and westbound entrance|
|144.4||232.4||IL 31 (State Street)|
|145.1||233.5||IL 25||Split into separate north and south exits westbound|
|Cook||146.4||235.6||Villa Street||Westbound exit and eastbound entrance; east end of Elgin Bypass|
|Bartlett||148.6||239.1||IL 59 (Sutton Road) – Barrington, West Chicago||Interchange|
|DuPage||Hanover Park||152.6||245.6||IL 390 east (Elgin–O'Hare Tollway) – O'Hare||Interchange; western terminus of IL 390|
I-355 south (Veterans Memorial Tollway) / I-290 west (Dwight D. Eisenhower Expressway) – Joliet, Chicago, Rockford
|I-355 exit 31|
|158.8||255.6||IL 53 (Rohlwing Road)|
|Addison– Elmhurst line||162.6||261.7|
IL 64 Truck west / IL 83 (Kingery Highway) to I-290
|Interchange; western end of IL 64 Truck overlap|
|I-290 west (Dwight D. Eisenhower Expressway) – Rockford||Western end of I-290 overlap; I-290 exit 12|
|164.8||265.2||I-290 east (Dwight D. Eisenhower Expressway) – Chicago||Eastern end of I-290 overlap; I-290 exit 13A|
IL 64 east ( North Avenue) / IL 64 Truck end
|Interchange; eastern end of IL 64 Truck overlap; eastbound left exit and westbound left entrance|
I-294 north ( Tri-State Tollway) – Wisconsin, O'Hare
|Tolled; no entrances from I-294|
|Berkeley||167.3||269.2||US 12 west / US 45 north ( Mannheim Road north)||Northern end of US 12/US 45 overlap|
|Bellwood– Hillside line||168.4||271.0||IL 56 west (Washington Boulevard)||Eastern terminus of IL 56|
|Hillside– Westchester line||169.2||272.3||I-290 / IL 110 (CKC) (Dwight D. Eisenhower Expressway) – Chicago||I-290 exit 17|
|169.7||273.1||IL 38 west ( Roosevelt Road)||Eastern terminus of IL 38|
|La Grange||172.9||278.3||US 34 ( Ogden Avenue)|
|Countryside||174.1||280.2||Historic US 66 (Joliet Road)|
|Hodgkins||176.8||284.5||I-55 (Aldai E. Stevenson Expressway) – Chicago, St. Louis||I-55 exit 279|
I-294 south (Tri-State Tollway) / IL 171 north ( Archer Avenue) / To 79th Street – Indiana
|Interchange; left exit eastbound|
|178.3||286.9||IL 171 south ( Archer Avenue)||Interchange|
|Hickory Hills||180.2||290.0||US 45 south ( La Grange Road south)||Southern end of US 45 overlap|
I-294 (Tri-State Tollway) – Wisconsin, Indiana
|Tolled; I-294 exit 17|
|182.9||294.3||IL 43 ( Harlem Avenue)||Cloverleaf interchange|
|Oak Lawn||185.9||299.2||IL 50 ( Cicero Avenue)|
|Chicago||191.0||307.4||To IL 1 ( Halsted Street) / I-94 east (Bishop Ford Freeway) / I-57|
|Stony Island Avenue||Northern terminus of Stony Island Avenue expressway (southbound); at-grade street northbound|
|196.5||316.2||US 41 north (Ewing Avenue north)||Northern end of US 41 overlap|
|197.9||318.5||I-90 west ( Chicago Skyway) / Toll Bridge||Tolled; signed as "To I-90 west"; access to I-90 east is in Indiana; I-90 exit 107|
|198.0||318.7||US 12 / US 20 east / US 41 south (Indianapolis Boulevard) – Hammond||Continuation into Indiana|
|1.000 mi = 1.609 km; 1.000 km = 0.621 mi|
The longest Business US 20 in Illinois runs 21 miles (34 km) from just west of Rockford to just east of Belvidere. The route begins just west of Weldon Road and runs as State Street into downtown Rockford, where it is split into two one-way streets (Chestnut Street and Walnut Street for eastbound traffic, Jefferson Street for westbound traffic). The route continues east along State Street all the way through Rockford and becomes a two-lane highway between Rockford and Belvidere. Business US 20 is then routed in an outer loop around the city of Belvidere before merging back with US 20 near Genoa Road and I-90.
Business US 20 in Elgin was removed in 1984. This ran along Larkin Avenue, Highland Avenue, Chicago Street and Villa Avenue. The current routing of US 20 south of Elgin is called the Elgin Bypass.
Business US 20 in Chicago was removed in 1968. This existed from 1960 through 1968; before then, it was City US 20 from 1938 to 1960. 
- Illinois Technology Transfer Center (2007). "T2 GIS Data". Retrieved November 8, 2007.
- Carlson, Rich (March 15, 2005). "Illinois Highways Page: Routes 1 thru 20". Retrieved April 15, 2006.[ self-published source]
- "IDOT Announces New Signs to Commemorate Ulysses S. Grant Memorial Highway" (Press release). Illinois Department of Transportation. August 31, 2007. Archived from the original on September 11, 2008. Retrieved September 8, 2007.
- Dees, Dan (November 1, 1974). "Illinois Supplemental Freeway System Proposal" (PDF). Illinois Department of Transportation. Retrieved January 11, 2015 – via Midwest Roads.
- "US 20 Freeport to Galena (Glacier Shadow Pass)". Illinois Department of Transportation. Retrieved January 12, 2015.
- Galena Gazette Staff (December 3, 2013). "Bustos Talks US 20 with Local Leaders". Galena Gazette. Retrieved January 11, 2015 – via Office of Cheri Bustos.
- "US 20 Galena Bypass". Illinois Department of Transportation. Retrieved January 11, 2015.
|U.S. Route 20|