Route 66 Alignments in Illinois
Illinois, a state known for its flat prairies and rich agricultural lands, also holds a significant place in the history of Route 66. This iconic highway, often romanticized as the "Mother Road," carved a diagonal path across the state, connecting Chicago to St. Louis. Unlike the challenging terrains of the southwestern states, Route 66 alignments in Illinois presented a relatively level journey. This ease of travel, however, belies the dynamic evolution of the road and its profound impact on the communities it traversed.
By the time Route 66 was officially commissioned in 1926, Illinois already boasted a well-developed road network. The newly designated highway largely followed the existing State Route 4, a heavily used, fully paved two-lane road. This meant that while other states were still grappling with the arduous task of paving their sections of Route 66, Illinois could proudly proclaim its segment to be "slab all the way" from the very beginning. This early advantage contributed to the rapid evolution of Route 66 alignments in Illinois.
The story of Route 66 alignments in Illinois is one of constant adaptation. Due to increasing population density and development pressures, the highway underwent continuous repairs, upgrades, widening, resurfacing, and rerouting. From its inception, engineers prioritized bypassing rural towns to facilitate a swift and unobstructed flow of traffic between Chicago and St. Louis. This focus on efficiency, however, gradually shifted the road away from its traditional main street course, foreshadowing the development of the interstate system that would eventually lead to its demise.
The strategic importance of Route 66 alignments in Illinois was further amplified during World War II. Designated as a strategic defense highway, it played a vital role in transporting goods to and from the major ordnance factories located outside of Chicago. This crucial function, however, took a toll on the roadbed, which was not designed to withstand the constant pounding of heavy munitions trucks. The Federal Government, through the Federal Defense Highway Act of 1941, provided significant funding for upgrades, laying the groundwork for the future four-lane, limited-access interstate system of the 1950s.
These transformations had a profound impact on the lives of people living along the Mother Road. Each rerouting and upgrade brought both opportunities and challenges. While a new alignment could bring welcomed business and travelers to a particular area, it could also devastate communities left behind. The modernization of the road into a four-lane highway was beneficial for motorists but could spell economic ruin for roadside establishments bypassed by the new route.
Today, despite being decommissioned in 1977, the spirit of Route 66 endures in Illinois. Much of the final alignment remains traversable, often under new designations. Several road segments have been recognized for their historical significance and listed in the National Register of Historic Places. These segments offer a tangible connection to the engineering achievements and the evolution of the road in Illinois. Let’s explore some of these remarkable sections of the Mother Road:
Road Segments of Route 66 in Illinois
Here is a closer look at some of the notable segments of Route 66 in Illinois, listed geographically from east to west:
Alternate Route 66, Joliet to Wilmington (1942-1967): This segment, extending from Welco Corners to Gardner, represents a significant chapter in the history of Route 66. It served as part of the original alignment until Joliet was bypassed. The main alignment was then rerouted through Plainfield, with the original pavement being designated as Alternate Route 66, later becoming Illinois Route 53.
The impacts of World War II and the Federal Government are central to the story of this segment. The original two-lane highway was deemed inadequate to handle the punishing wartime traffic to and from the nearby Kankakee and Elmwood ordnance plants. As a result, it was replaced with a limited-access four-lane divided highway constructed between 1942 and 1945, authorized and funded by the Federal Defense Highway Act of 1941. Updated construction methods were employed, including a unique sub-base of gravel and stone on top of the older roadbed and a divided 24-foot wide roadbed with a 10-inch thick Portland cement slab.
According to Dwight Cannon, 2024 President of the Route 66 Association of Illinois, sections of the Plainfield alignment still exist, some now under I-55, and others labeled as IL 129. An original section north of Elwood, currently marked as Chicago Road and then Mississippi Road, was the actual alignment heading into Elwood until it was bypassed.
This segment remained a crucial transportation artery until the arrival of Interstate I-55 in 1956. Despite a new macadam overlay, much of the road’s original 1945 character remains intact. Travelers should look for the 1942 Union Pacific Overpass near the northern end of the segment and four remaining box concrete culverts. To explore this section, begin at Patterson Road in Joliet and travel south on Highway 53 toward Wilmington, ending at the junction of Highway 53 (Alternate Route 66) and Illinois Route 102 (Water Street) in downtown Wilmington.
Route 66 by Carpenter Park, Springfield (1922-1936): Please note that as of November 2024, this segment is marked with "No Trespassing" signs. This short, abandoned roadbed, stretching for about one-quarter mile on the north bank of the Sangamon River in north Springfield, offers a unique glimpse into the past. Untouched by automobile traffic since 1936, it evokes the feeling of an archeological site. The two-lane, 16-foot wide road reflects the engineering and design methods of its construction time in 1922 and serves as a good example of how existing paved roads were redesignated as Illinois Route 66 in 1926.
In 1922, this roadway was paved with cement and gravel, with expansion joints placed every 30 yards. Its original four-foot gravel shoulders and four-inch curbs still flank parts of the road. Its life as Route 66 was short, as engineers quickly began work on a new, wider (four-lane) alignment a few yards to the east, completed in 1936. The Carpenter Park segment remains intact primarily because it has not carried traffic since then, although the Old Iron Bridge over the Sangamon River is no longer present.
With the decommissioning of the road in 1936, the bridge was dismantled, leaving only concrete abutments. This segment is now part of Carpenter Park on the far north side of Springfield, Illinois. Visitors are welcome to walk on this stretch of Route 66, surrounded by a forest preserve of native hardwood. The entire segment is contained within the park’s boundaries. The 322-acre park is also an Illinois Nature Preserve, owned by the city of Springfield and overseen by the Illinois Department of Natural Resources.
Route 66, Cayuga to Chenoa (1943-44; 1954-55): The original 1920s pavement of this segment, boasting a width of 18 feet and a Portland cement slab six inches deep, proved insufficient for the demands of Route 66’s World War II mission. The excessive weight and volume of wartime traffic severely damaged the narrow roadbed, necessitating a significant upgrade.
A 1943-44 wartime makeover included two lanes of 24-foot wide, ten-inch thick concrete. The sections were generally striped for 11-foot driving lanes, an extension of two feet over the older pavement. The southbound lanes, constructed directly over the older roadbed, were finished in 1944, and the northbound lanes were completed in 1954-55, creating a four-lane highway with a center median. Today, the northbound lanes have a new macadam overlay, but the southbound lanes retain their original concrete surface for the most part. The segment retains six historic bridges.
Route 66, Litchfield to Mount Olive (1943-1955): As with other segments of Route 66, the stretch from Litchfield to Mount Olive was transformed as a result of World War II. By 1942, the original alignment had significantly deteriorated under the stress of wartime traffic. Authorized by the Federal Defense Highway Act of 1941, the approach to constructing this segment reflects both the pressures of wartime conditions and the long-term postwar vision of transforming Illinois Route 66 into a modern, limited-access freeway between Chicago and St. Louis.
The new two-lane road, with a pavement of Portland cement, 24-foot wide and 10 inches thick, was set down just to the west of the older route, which had been constructed in 1930-31. The older, deteriorated pavement was kept in service until the new alignment was complete. When the new Route 66 southbound lanes were completed in 1943, the older alignment was designated Old Route 66 and remained open to local traffic. Construction of the northbound lanes had to wait until after the war. Still, when completed in 1954-55, they formed, along with the 1943-44 southbound lanes, a state-of-the-art four-lane highway with a center median – a veritable precursor to the Interstate freeway.
Pre-1930 Segment of Route 66 – Chatham to Staunton: This section is one of the oldest and most scenic portions of Route 66 in Illinois. It follows the old Pontiac Trail, the primary route between Chicago and St. Louis in the early 1900s. This pre-1930s alignment meanders through several towns before rejoining the later alignment south of Staunton.
Illinois Route 4, North of Auburn (1921-1932): This bypassed portion of old Route 4 north of Auburn, Illinois, is listed in the National Register of Historic Places. It consists of a 1932 1.53-mile-long brick road and a 1921 Portland cement road. Both are well-preserved examples of Route 66’s early years in Illinois, illustrating early highway-era construction methods.
Route 66, Girard to Nilwood (1919-1931): This segment was designated as a part of the Mother Road in 1926 but was quickly replaced in 1930 with a major realignment to the east. Constructed in 1920 as part of old State Route 4, this short-lived section of Illinois Route 66 is typical of the engineering and construction methods of the post-World War I era.