U.S. Route 24

US 24 looking out on Cascade, Colorado, viewed from the Pikes Peak Highway

In Colorado, US 24 begins at the interchange of I-70 and US 6 (exit 171) near Minturn. From this interchange, US 24 proceeds southeast through Minturn and continues south to the Continental Divide at Tennessee Pass. It continues south to Johnson Village and then joins with US 285 northbound to Trout Creek Pass. After the pass, US 24 separates from US 285 and continues east to Colorado Springs and then northeast to Limon, where US 24 joins I-70 for most of the rest of its routing to the Kansas state line.

When the U.S. Numbered Highway System was started in 1926, US 24 in Colorado was designated US 40S. It began in Grand Junction and went east along the current I-70 corridor to Minturn, from which it followed the current route to Limon. From Limon east to the Kansas border, the current US 24 was designated US 40N. US 40S west of Limon and US 40N east of Limon received the US 24 designation in 1936, when US 24 was extended west from Kansas City, Missouri. The segment between Grand Junction and Minturn was decommissioned in 1975.

In Kansas, US 24 enters from Colorado west of Kanorado; it overlaps I-70 for 45 miles (72 km) to Colby. US 24 does not meet I-70 again until Kansas City. On December 1, 2008, US 24 was rerouted southward on US 73 to I-70 west of Kansas City, continuing east on I-70 on the final 16 miles (26 km) in Kansas.[9] US 24 serves Manhattan, as well as the northern sides of Topeka and Lawrence.

The original designation for the current US 24 route in Kansas was US 40N. It went from the Colorado border to Manhattan. In 1936, US 24 received its current designation after an extension west from Kansas City.

In Kansas, US 24 is merged with US 59 from Williamstown to a place in northern Lawrence called Teepee Junction. From there, it is merged with US 40 until Kansas City.

In Missouri, US 24 serves Kansas City, Independence, Buckner, Lexington, Waverly, Carrollton, Keytesville, Moberly, Madison, Monroe City, Palmyra, and West Quincy. It runs concurrently with US 65 between Waverly and Carrollton, passing over the Missouri River via the Waverly Bridge when concurrent. After becoming a two-lane road, it is then concurrent with Route 5 in Keytesville (where it is called Jackson Street) and then passes by the city of Huntsville before turning into a four-lane highway and crossing US 63 at Moberly. It is finally concurrent (for the third time) with US 36 east of Monroe City and with US 61 from south of Palmyra to West Quincy. The segment shared with US 61 is part of the Avenue of the Saints.

Along the route within Independence is the Harry S. Truman Presidential Library and Museum.

Crossing into Illinois, US 24 uses the pairing of the cable-stayed Bayview Bridge (westbound) and the older Quincy Memorial Bridge (eastbound) over the Mississippi River in Quincy. As of 2006, it is the main arterial highway from Quincy northeast to Peoria. Between these two cities, the highway follows the old Peoria to Quincy stage coach route. US 24 travels onto the Shade–Lohmann Bridge on I-474 to bypass Peoria, and it gets off at exit 9.

In East Peoria, US 24 forms a wrong-way concurrency with Illinois Route 116 and US 150 as it parallels the Illinois River. From East Peoria, US 24 runs directly east (parallel to the Toledo, Peoria and Western Railway) through a number of small towns en route to Indiana. US 24 crosses into Indiana at the state line east of Sheldon.

In Indiana, US 24 runs east from the Illinois state line to Huntington. At Huntington, US 24 turns northeast and runs to Fort Wayne; it then overlaps I-69 and I-469 to bypass the city before entering Ohio at the state line east of Fort Wayne. The segment of US 24 between Logansport and Toledo, Ohio, is part of the Hoosier Heartland Industrial Corridor project of the Intermodal Surface Transportation Efficiency Act.

From Fort Wayne, US 24 follows the path of the Maumee River toward Toledo. In Ohio, the roadway enters the state east of Woodburn, Indiana, near Antwerp. Between the Indiana state line and Toledo, this portion of the roadway is known as the Fort to Port segment of the Hoosier Heartland Industrial Corridor.

Between Napoleon and Toledo, modern US 24 lies north of the Maumee River as a highway built to Interstate Highway standards. Just north of Waterville is the site of the Battle of Fallen Timbers of 1794. General Anthony Wayne after constructing a trail from Fort Wayne to (Fort) Defiance, fought and defeated a Native American consortium, thus opening northern Ohio to white settlement. At a point on Toledo's north side, US 24 veers from northeast–southwest to true north–south, turning on to Telegraph Road, while Detroit Avenue continues as a city street that connects to M-125 (Dixie Highway) at the Michigan border.

The path through Toledo of US 24 follows the course of old US 25, old US 25 being farther away from the course of north–south I-75. Partially truncated as a state route, what had been US 24 was renumbered as State Route 25 where it remained a state highway, and US 25 in greater Toledo became US 24.

In Michigan, US 24 enters from Toledo, Ohio, and serves the city of Monroe and Metro Detroit, where it is known as Telegraph Road. It continues north through the western edge of Detroit. It passes through Michigan's "mixing bowl", which is where I-696 (Walter P. Reuther Freeway), M-10 (John C. Lodge Freeway/Northwestern Highway), and Lahser Road intersect. US 24 continues north along Telegraph Road as the border between Waterford and Pontiac until its intersection with Dixie Highway where it travels to the northwest until its termination at I-75 in Independence Township.