M-66 (Michigan highway)

M-66 marker
M-66
Map
M-66 highlighted in red
Route information
Maintained by MDOT
Length266.399 mi[1] (428.728 km)
Existedc. July 1, 1919[2]–present
Major junctions
South end SR 9 near Sturgis
Major intersections
North end US 31 at Charlevoix
Location
CountryUnited States
StateMichigan
CountiesSt. Joseph, Branch, Calhoun, Barry, Eaton, Ionia, Montcalm, Mecosta, Osceola, Missaukee, Kalkaska, Antrim, Charlevoix
Highway system
M-65 M-67

M-66 is a north–south state trunkline highway on the Lower Peninsula of the US state of Michigan. It runs from the Indiana state line in the south to Charlevoix in the north. M-66 is the only state highway to run the north–south distance of the Lower Peninsula. It starts as a continuation of State Road 9 (SR 9), which provides access to the Indiana Toll Road. The total length is approximately 272.9 miles (439.2 km), which includes almost 3.4 miles (5.5 km) of freeway between Interstate 94 (I-94) and downtown Battle Creek designated as I-194. A section of the highway immediately south of I-94 is an expressway, a type of divided limited-access highway, while the section along I-194 is a full freeway; otherwise M-66 is a two-lane rural highway. Two sections are listed on the National Highway System.

The first usage of the M-66 designation dates back to around July 1, 1919 with the rest of the original state highway system. At the time, the highway only extended between Lowell and Lakeview, a route now covered by M-91. The highway has been lengthened in a series of extensions north and south starting in 1925. A rerouting in 1944–45 removed M-66 from its original 1919 routing to replace another highway south of Six Lakes, the change that spawned M-91. The last big extension in 1965 resulted in the modern trans-peninsular highway route. The last modifications were shorter reroutings in the 1970s.

  1. ^ Cite error: The named reference PRFA was invoked but never defined (see the help page).
  2. ^ Michigan State Highway Department (July 1, 1919). State of Michigan (Map). Scale not given. Lansing: Michigan State Highway Department. Lower Peninsula sheet. OCLC 15607244. Retrieved October 17, 2019 – via Michigan History Center.