&sq=Google&lang=en&file=File:M-81.svg) M-81 | ||||
|---|---|---|---|---|
 M-81 highlighted in red | ||||
| Route information | ||||
| Maintained by MDOT | ||||
| Length | 45.636 mi[1] (73.444 km) | |||
| Existed | c. July 1, 1919[2]–present | |||
| Major junctions | ||||
| West end |  M-13 in Saginaw | |||
| East end |  M-53 near Cass City | |||
| Location | ||||
| Country | United States | |||
| State | Michigan | |||
| Counties | Saginaw, Tuscola, Sanilac | |||
| Highway system | ||||
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M-81 is an east–west state trunkline highway in the Lower Peninsula of the US state of Michigan. The trunkline travels from the city of Saginaw at the junction with M-13 to the junction with M-53 east of Cass City over the county line in Greenleaf Township in northwestern Sanilac County in The Thumb area of the state. Outside of the cities and villages along its route, M-81 passes through mostly rural farm country. Near Saginaw it intersects the freeway that carries both Interstate 75 (I-75) and US Highway 23 (US 23) in an industrial area.
A road bearing the M-81 designation has existed since at least July 1, 1919, when the state initially numbered its trunkline highways. Since that time, it has been extended, rerouted or shortened several times. These changes resulted in essentially the modern highway routing by 1926; the highway was fully paved in the 1940s. A change made in 1929 was reversed in 1933, and an extension through downtown Saginaw in the 1960s was overturned in the 1970s. The last change was the construction of a pair of roundabouts at the I-75/US 23 interchange in 2006.