In the U.S. state of Illinois, U.S. Route 67 is a north–south highway through the western portions of the state. It runs from the Clark Bridge in Alton north to the Rock Island Centennial Bridge in Rock Island. This is a distance of 213.99 miles (344.38 km).

U.S. 67 is the major north–south corridor for western Illinois, and the only major Illinois north–south highway route from 1918 that was never upgraded to the Interstate highway system.

From Macomb to Monmouth, US 67 is currently a "Super Four" 65 mph (105 km/h), four-lane highway. The Roseville Bypass was completed in 2003.

In 1918, the Illinois State Legislature established State Bond Issue (SBI) for the establishment of a state road system. The route for Illinois 3 went from Cairo Junction to Morrison via Rock Island.

With the completion of highway bridges over the Mississippi River, Route 67 was extended from St. Louis to Godfrey and replaced the original Illinois 3 to Rock Island.

The original northern terminus of US 67 was in Missouri under the US highway enumeration scheme of 1926, likely due to limited bridge crossings over the Mississippi and Missouri Rivers. By 1932, with a Mississippi River crossing route determined, US 67 was extended north along Illinois Route 3 to Rock Island.

Even though the Old Clark Bridge had been opened to traffic across the Mississippi River at Alton in 1928, US 67 originally crossed the Mississippi River with U.S. Route 66 via the McKinley Bridge from St. Louis to Venice. From Venice, US 67 headed north along what had been Illinois 3 via Alton to Rock Island. The original route of IL 3 from Alton to Jacksonville that became US 67 went through East Newbern, Jerseyville, and Carrollton.

In 1926, the northern terminus of U.S. Route 67 was at Alt. US 61 near Fredericktown, Missouri. The route was extended north on Illinois Route 3 (through western Illinois) to its northern terminus in Rock Island, Illinois by 1932. Sometime after 1940, US 67 was routed into Madison County. Then, it was co-signed with Route 66 as both routes went across the McKinley Bridge.

By the mid-1940s, US 67 had been rerouted from St. Louis to Alton via the Lewis Bridge over the Missouri River and the Clark Bridge (formerly the Old Clark Bridge) over the Mississippi River. The Alton to Jerseyville section now passed through Godfrey and Delhi. By the mid-1950s, a more direct route for US 67 from Godfrey towards Jacksonville via Greenfield had opened. Heading north from downtown Alton, US 67 was rerouted via an abandoned railroad grade to the north end of town.

Between Fort Bellefontaine, Missouri (near Lewis Bridge) and south of St. Louis, US-67 followed two different routes. Route 67 originally followed Lewis and Clark Blvd. south to St. Louis, while Alternate US-67 turned west on Lindbergh Blvd. through Florissant past Lambert/St. Louis Int'l airport. Alt 67 was reposted as Route 267 along Lindbergh Blvd. In the late 1960s these routes were "flipped" with US-67 proceeding through Florissant and Hazelwood.

In 1962 another reroute took place, due to the completion of a new river bridge over the Illinois River at Beardstown. A new direct route was constructed from this bridge at Beardstown to Rushville, eliminating the earlier US-67 eastern route northeast along current IL-100 to Frederick then turning north to Rushville. A western bypass of downtown Rushville was completed a couple of years later.

In 1964, Route 3 replaced US 67A as St. Louis started to eliminate highways such as 67A. A new four-lane Route 3 opened a few years later.

In 1968, US-67 was rerouted on a more western route between Jacksonville and Beardstown. The route was the existing IL-104 (Jacksonville to near Merodosia) and IL-100 (near Merodosia to Beardstown). The original US-67 road passed through Virginia on what is now IL-78 (Jacksonville to Virginia) and then on IL-125 (Virginia to Beardstown), which follows the historic Beardstown Post Road and Ohio & Mississippi Railroad right-of-way (later part of Baltimore and Ohio Railroad (B&O) system before abandonment) between Beardstown and Springfield.

Before 1994, US 67 passed through Alton on Belle Street. After 1994, US 67 got a new bridge as well as a new route through Alton. In the summer of 1994, parts of the road were demolished in a span of 8-10 weeks. Today, planners from Godfrey and Jerseyville are discussing a new US 67 that would take a western route along the current IL 267.

These routes remained in common usage even after they were deleted in 1964:

There were two Alt US 67's in Madison County. The first started south of Alton, the second, north. When US 67 was switched to the Clark Bridge sometime before the mid-1940s, the earlier route of US 67 from St. Louis to Alton became Alt US 67. In the mid-1940s, Alt US 67 was switched from the McKinley Bridge to the MacArthur Bridge. By 1965, the Alt US 67 designation had been dropped and the IL 3 designation had returned to this route. The original IL 3 roadway had been replaced by new alignments in places over the years, however. When US 67 was shifted to a more direct route north of Alton between Godfrey and Jacksonville by the mid-1950s, the old route via Jerseyville and Carrollton became Alt US 67. This designation lasted until around 1965 when the route became IL 267.

Illinois Route 267 was once Alt US 67 from the mid-1950s to 1965 as it went from Godfrey through Jerseyville on its way to meet up with US 67 about ten miles (16 km) south of Jacksonville. This route, despite being one of the most dangerous in central Illinois, has remained unchanged over the years.

In 2001, IDOT rerouted US-67 back onto the original (1940) routing (western route) north of Alton to Murrayville and IL-267 was put onto the newer alignment (eastern route) from near Murrayville through Greenfield to Medora. South of Medora to Godfrey the road retained only IL-111, a second number on this section. The rerouting was to accommodate a future "Corridor 67" expressway that will be built within the next decade or so. IDOT construction began in 2004 near Jacksonville. The new expressway is supposed to follow the corridor through White Hall, Carrollton, and Jerseyville and will end in Godfrey.