U.S. Route 23 in Michigan

US Highway 23
US 23 highlighted in red
Route information
Maintained by MDOT
Length:	362.152 mi (582.827 km)
Existed:	November 11, 1926 (1926-11-11) – present
Tourist routes:	Lake Huron Circle Tour Huron Shores Heritage Route
Major junctions
South end:	US 23 / US 223 near Lambertville
	I-94 near Ann Arbor I-96 in Brighton I-75 near Flint I-69 in Flint US 10 in Bay City I-75 near Standish
North end:	I-75 near Mackinaw City
Location
Counties:	Monroe, Washtenaw, Livingston, Genesee, Saginaw, Bay, Arenac, Iosco, Alcona, Alpena, Presque Isle, Cheboygan, Emmet
Highway system
United States Numbered Highway System List Special Divided Replaced Michigan State Trunkline Highway System Interstate US State Byways ← M-22 M-23 →

US Highway 23 (US 23) is a United States Numbered Highway that runs from Jacksonville, Florida, to Mackinaw City, Michigan. In the US state of Michigan, it is a major, 362-mile-long (583 km), north–south state trunkline highway that runs through the Lower Peninsula (LP). The trunkline is a freeway from the Michigan–Ohio state line near Lambertville to the city of Standish, and it follows the Lake Huron shoreline from there to its northern terminus. Serving the cities of Ann Arbor and Flint, US 23 acts as a freeway bypass of the Metro Detroit area. Overall, the highway runs through rural areas of the state dominated by farm fields or woodlands; some segments are urban in character in the Ann Arbor, Flint and Tri-Cities areas. The section from Flint north to Standish also carries Interstate 75 (I-75) along a concurrency that includes a segment that carries almost 70,000 vehicles on a daily basis.

The first transportation routes along what is now US 23 in the state were sections of two Indian trails. The route of what is now US 23 follows portions of two separate trails. In the early 20th century, four different auto trail names were applied to roads now a part of the highway. These roads were included as part of two state highways in the initial state highway system in 1919. When the United States Numbered Highway System was first designated on November 11, 1926, the new US 23 replaced the other designations along its route. Since creation, the road has been moved and realigned several times. Through the 1930s and 1940s, the lakeshore routing was created to replace a path that ran further inland through the northern portion of the state. Starting in the early 1950s, various sections in the southeastern and central areas of the LP were upgraded to freeways, bypassing several major cities in the area. These improvements were completed by the end of the 1960s. Since then a new crossing of the Saginaw River at Zilwaukee was built to replace a drawbridge that carried the I-75/US 23 freeway over a shipping channel.