Minnesota State Highway 78 (MN 78) is a highway in west-central Minnesota, which runs from State Highway 79 near Erdahl and continues north to its northern terminus at its interchange with U.S. Highway 10 in Perham.
State Highway 78 was authorized in 1933. The south portion of Highway 78 was still gravel in 1953. All of the route was paved by 1960. ==Major intersections==