Illinois Route 53 is an arterial north–south state highway in northeast Illinois. Route 53 runs south from Long Grove at Illinois Route 83 to Gardner at Interstate 55 west of old U.S. Highway 66, a distance of 82.02 miles (132.00 km). It mainly cuts through the western suburbs of Chicago, passes through Joliet, Crest Hill and straddles I-55 at its southern extent.

Illinois 53 is one of the state highways routed along expressways in the state. Before it becomes an expressway, Illinois 53 starts out in Long Grove going southwest towards Palatine. South of Lake-Cook Road, Illinois 53 follows Hicks Road, Rand Road (concurrent with U.S. 12) and Dundee Road (concurrent with Illinois 68) through Palatine's northeast side before it joins an expressway that starts un-numbered (technically a spur of 53), one mile (1.6 km) north at Lake-Cook Rd as a bypass of northeast Palatine. The northeast Palatine stretch goes through the Rand and Dundee intersection, one of the country's deadliest intersections in traffic accidents.[citation needed] It forms the other half of the Interstate 290/IL 53 combination in Schaumburg before being routed west onto Biesterfield Road and back south onto Rohlwing Road. Until its first junction with I-55 by Bolingbrook, it remains a mostly 2 to 4 lane road, largely replaced by the I-290 and I-355 combo. In the suburb of Lombard, Illinois 53 is called Columbine Avenue.

South of the first junction with I-55, Illinois 53 follows old U.S. 66 and parallels Interstate 55, entering downtown Joliet, which is about four miles (6 km) east of I-55. Illinois 53 also passes directly in front of Stateville Correctional Center in Crest Hill, Illinois. From Joliet it follows the original U.S. 66 alignment to the south. It remains a four-lane divided highway for about 15 miles (24 km), passing through Elwood and the former Joliet Army Ammunition Plant, part of which is now occupied by the Abraham Lincoln National Cemetery. Route 53 narrows to two lanes just outside Wilmington and crosses the Kankakee River in downtown Wilmington. It then continues southwest through Braidwood and Braceville on its way to Gardner, where it loops around the southern part of town before ending at I-55.

SBI Route 53 ran from Romeoville to Long Grove on Rohlwing Road and Hicks Road from 1924 to 1963. From 1963 through 1970, it was routed onto a new freeway from Addison to Arlington Heights and cosigned with Interstate 90 until that was changed to Interstate 290.

In 1967 Illinois 53 was extended to Gardner, and in 1995 Illinois Route 129 was routed onto Illinois 53 south of Braidwood. This lasted a year until Illinois 129 was dropped entirely south of Braidwood. Near the northern end, the freeway was extended from Dundee Road to Lake-Cook Road in 1989.

In 1990, with the construction of Interstate 355, Illinois 53 was moved off of the Interstate 290/355 combination south of Biesterfield Road and back onto its original alignment.

Illinois 53 has been at the center of a major dispute regarding its northern extension (also known as FAP 342) into Lake County. The studied corridor currently runs from its current terminus at Lake-Cook Road north to a planned bypass for Illinois Route 120 near Grayslake. FAP 342 road signs are posted on roads that would be crossed by the proposed extension, demarking the right-of-way (many villages have not allowed development in the proposed right-of-way). The combined 53/120 extension would form a large T shape in the center of Lake County, with the 120 bypass carrying through-traffic from U.S. Route 12 to the Tri-State Tollway around Gurnee.

Once proposed as a freeway following Interstate standards, then considered dead, it is now proposed as a limited speed (45 mph) tollway.

The highway has been opposed by several organizations, notably the Illinois chapter of the Sierra Club and vocal residents of Long Grove, which lies directly in the path of the Illinois 53 extension. The Sierra Club opposes the roadway extension due to wetlands in the corridor, fear of suburban sprawl and other factors. Instead, they call for expanding existing roads. Funding has also been a long term concern.

Proponents of the tollway argue that congestion in Lake County has already reached economically damaging levels, and the existing network of roads in the county is insufficient for the task; and that future projections call for housing and commerce development to reach the McHenry and Lake County areas regardless of the presence of a new highway. In April 2009, voters in Lake County approved (76% "Yes" to 24% "No") a non-binding referendum in favor of constructing the Illinois 53 extension.

In a separate section to the south, the Illinois Department of Transportation proposed in 1999 of widening Illinois 53 south of U.S. Route 20 (Lake Street) and generally north of Interstate 88 to a five-lane section. Opposition from a citizen group called NIFTI (Neighbors Influencing Fifty-Three improvement) began to lobby for a smaller expansion plan of three-lanes. The road south of Lake Street runs through predominantly residential areas and light industry. The term Context Sensitive Design and Solutions was introduced to the state of Illinois through the efforts of this group.