M-124 is a state trunkline highway in the Lower Peninsula of the US state of Michigan that runs on the north side of Vineyard and Wamplers lakes near Brooklyn in Jackson County near the Irish Hills area.

The highway travels directly through W. J. Hayes State Park before ending in Lenawee County.

The designation was created in 1929 for a road that accessed the state park, connecting it to US Highway 112 (US 112, now US 12).

[4][5] The park is a popular tourist destination for boaters, craft and antique shows and its close proximity to Michigan International Speedway.

[7] No segment of M-124 is listed on the National Highway System,[8] a network of roads important to the country's economy, defense, and mobility.