The route of M-125 changes direction slightly as it passes through the community of LaSalle; north of town it follows a more northeasterly course. The roadway passes through residential areas north of town as it approaches Monroe. South of the city, M-125 crosses the La Plaisance Creek and turns north-northwesterly through South Monroe. North of Lake Monroe, the road name changes from Dixie Highway to Monroe Street. The highway is the main street of the downtown area as it crosses the River Raisin upstream from the River Raisin National Battlefield Park. M-125 exits town near The Mall of Monroe. About north of Monroe, after running through farm land again, M-125 terminates at an intersection where Dixie Highway merges into US 24 (Telegraph Road).