Route 4: The Grandmother of Route 66 in Illinois

Got story updates? Submit your updates here. ›

Illinois Route 4 has a storied history as one of the oldest and longest numbered highways in the state. Originally stretching from Chicago to St. Louis, much of Route 4's alignment was later designated as the new Route 66 in 1926. This makes Route 4 the 'grandmother' of the famous Route 66, which is often referred to as the 'Mother Road.' While Route 4's modern path is much shorter, running from Springfield to Murphysboro, it continues to honor its legacy as a pioneering highway in Illinois.

Why it matters

Route 4's history provides insight into the early development of Illinois' highway system and the origins of the iconic Route 66. As one of the state's first numbered highways, Route 4 laid the groundwork for the creation of Route 66, which became one of the most famous roads in America. Recognizing Route 4's role helps preserve an important part of Illinois transportation history.

The details

Illinois Route 4 was created in 1918 as part of the state's $60 million bond issue to build 4,800 miles of new roads. The route originally stretched from Chicago to St. Louis, following the path of an older Indian trail and stagecoach route. When Route 66 was commissioned in 1926, much of its alignment in Illinois was designated over the existing Route 4 pavement. Route 4 continued to exist concurrently with Route 66 until 1935, when the Route 4 designation was removed from the shared alignment. The modern Route 4 now runs from Springfield to Murphysboro.

• Route 4 was created in 1918 as part of a $60 million bond issue for new roads in Illinois.
• Route 66 was commissioned on November 11, 1926, with much of its Illinois alignment designated over the existing Route 4.
• In 1928, a new section of Route 66 was built east of the original Route 4 alignment between Springfield and Staunton.
• The Route 4 designation was removed from the shared Route 66 alignment in 1935.
• In 1964, the current Route 4 alignment from Springfield to Murphysboro was established.