US Highway 23 (US 23) is a north–south 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. 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.

Mackinaw City is a village at the northernmost point of the Lower Peninsula of Michigan, United States. Divided between Cheboygan and Emmet counties, Mackinaw City is located at the southern end of the Mackinac Bridge, which carries Interstate 75 over the Straits of Mackinac to the Upper Peninsula. Mackinaw City, along with St. Ignace, serves as an access point to Mackinac Island. For these reasons, Mackinaw City is considered one of Michigan's most popular tourist attractions.