M-10 is a state trunkline highway in the Metro Detroit area of Michigan in the United States. Nominally labeled north-south, the route follows a northwest-southeast alignment. The southernmost portion follows Jefferson Avenue in downtown Detroit, and the southern terminus is at the intersection of Jefferson and M-3 next to the entrance to the Detroit–Windsor Tunnel. The northern terminus is in West Bloomfield Township at the intersection with Orchard Lake Road. The highway has several names as it runs through residential and commercial areas of the west side of Detroit and into the suburb of Southfield. It is called the John C. Lodge Freeway, James Couzens Highway, and Northwestern Highway. One segment has also been named the Aretha Franklin Memorial Highway.

The State Trunkline Highway System consists of all the state highways in Michigan, including those designated as Interstate, United States Numbered, or State Trunkline highways. In their abbreviated format, these classifications are applied to highway numbers with an I-, US, or M- prefix, respectively. The system is maintained by the Michigan Department of Transportation (MDOT) and comprises 9,669 miles (15,561 km) of trunklines in all 83 counties of the state on both the Upper and Lower peninsulas, which are linked by the Mackinac Bridge. Components of the system range in scale from 10-lane urban freeways with local-express lanes to two-lane rural undivided highways to a non-motorized highway on Mackinac Island where cars are forbidden. The longest highway is nearly 400 miles (640 km) long, while the shortest is about three-quarters of a mile. Some roads are unsigned highways, lacking signage to indicate their maintenance by MDOT; these may be remnants of highways that are still under state control whose designations were decommissioned or roadway segments left over from realignment projects.