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.
M-78 is a state trunkline highway in the US state of Michigan. The western terminus is the intersection with M-66 north of Battle Creek in Pennfield Township. The roadway runs 10.744 miles (17.291 km) through rural farmland and the community of Bellevue as it approaches its eastern terminus at an interchange with Interstate 69 (I-69) near Olivet. The highway is used by between 3,100 and 5,300 vehicles on a daily basis.
M-89 is an east–west state trunkline highway in the US state of Michigan that runs from near Ganges to Battle Creek. M-89 starts at an interchange with Interstate 196/US Highway 31 (I-196/US 31) and passes through Allegan, Kalamazoo County, Michigan, and Calhoun counties. The highway also briefly crosses the southwest corner of Barry County before it terminates an at intersection with Business Loop I-94 on the northwestern side of downtown Battle Creek. In between the trunkline runs parallel to the Kalamazoo River through rural southwestern Michigan farmlands while also running through the middle of several smaller towns in the area.
M-21 is an east–west state trunkline highway in the US state of Michigan connecting the cities of Grand Rapids and Flint. The highway passes through rural farming country and several small towns along its course through the Lower Peninsula. Following the course of a handful of rivers, M-21 also connects some of the state's freeways like Interstate 96 (I-96), US Highway 127 (US 127) and I-75. The highway is used by between 1,700 and 36,000 vehicles daily.
Interstate 196 (I-196) is an auxiliary Interstate Highway that runs for 80.6 miles (129.7 km) in the US state of Michigan. It is a state trunkline highway that links Benton Harbor, South Haven, Holland, and Grand Rapids. In Kent, Ottawa, and Allegan counties, I-196 is known as the Gerald R. Ford Freeway, or simply the Ford Freeway, after President Gerald Ford, who was raised in Grand Rapids and served Michigan in the House of Representatives for 25 years. This name generally refers only to the section between Holland and Grand Rapids. I-196 changes direction; it is signed as a north–south highway from its southern terminus to the junction with US Highway 31 (US 31) just south of Holland, and as an east–west trunkline from this point to its eastern terminus at an interchange with I-96, its parent highway. There are three business routes related to the main freeway. There are two business loops and one business spur that serve South Haven, Holland and the Grand Rapids areas. Another business spur for Muskegon had been designated relative to the I-196 number.
M-46 is an east–west state trunkline highway in the US state of Michigan between Muskegon and Port Sanilac, terminating near Lake Michigan and Lake Huron on each end. Except for the north–south segment that corresponds with the US Highway 131 (US 131) freeway between Cedar Springs and Howard City, M-46 is practically a due east–west surface highway. The road runs through rural sections of the Lower Peninsula connecting several freeways including US 31, US 131, US 127 and Interstate 75 (I-75).
M-120 is a state trunkline highway in the US state of Michigan in the southwest Lower Peninsula. The highway runs northeast from Muskegon to Hesperia. In between, the road passes through suburban Muskegon, forests and farmland. Some 5,900–26,000 vehicles use the highway each day on average as it runs long a series of roads that follow county lines in the area.
M-47 is a north–south state trunkline highway in the US state of Michigan. It runs near Saginaw and Midland in the Tri-Cities area of the Lower Peninsula. The highway runs through suburban and agricultural areas to connect the two cities with the airport in the area. The northernmost section of M-47 runs along a freeway to the terminus at US Highway 10 (US 10). M-47 runs for 14.328 miles (23.059 km), all of which has been listed as a part of the National Highway System.
M-91 is a largely north–south state trunkline highway in the Lower Peninsula of the US state of Michigan. It runs from Belding to south of Lakeview. Its 24-mile (39 km) length exists entirely within Ionia and Montcalm counties. It is all undivided surface route. Aside from the two Michigan state highways that are its termini, it has only one other intersection with any Michigan state highway, and that is with M-57 in Greenville.
M-55 is a state trunkline highway in the northern part of the US state of Michigan. M-55 is one of only three state highways that extend across the Lower Peninsula from Lake Huron to Lake Michigan; the others are M-46 and M-72. The highway crosses through rural forest and farmlands to connect Manistee with Tawas City. M-55 crosses two of the major rivers in the state. Two sections of the highway follow along freeways near Cadillac and West Branch. Running for 150.944 miles (242.921 km) through the state, M-55 is maintained by the Michigan Department of Transportation (MDOT).
M-18 is a north–south state trunkline highway in the Lower Peninsula of the US state of Michigan. It runs for 77.530 miles (124.772 km) through the central region of the state connecting US Highway 10 (US 10) near North Bradley with M-72 in rural Crawford County near the community of Luzerne. In between, the roadway connects several smaller communities while running through woodlands in both state and national forest areas. Two segments of M-18 run along sections of county boundaries, and one part of the highway forms a component of the business loop for the village of Roscommon.
M-82 is a state trunkline in the Lower Peninsula in the US state of Michigan that travels between Fremont and Howard City. The section between Newaygo and Howard City travels through Fremont and along the southern edge of Manistee National Forest. The current version of M-82 is actually the second in the state; the first usage appeared in the Upper Peninsula by 1919. The Lower Peninsula routing has been in use since the 1920s. Various extensions and truncations have shifted the terminus as far west as New Era or Hesperia in the past. The current route was finalized in the late 1970s
There are three business routes of US Highway 10 (US 10) in the state of Michigan. They serve as connections from the main highway into Reed City, Clare, and Midland. Additionally, there were another two business routes that connected US 10 to the downtowns of Flint and Pontiac. All these business routes are, or were, former sections of US 10 that were marked Business US Highway 10 after the main highway was realigned to bypass the downtowns of the cities.
There are six business routes of US Highway 131 in the state of Michigan, and previously there was one bypass route and an additional business route. All of the business routes are former sections of US Highway 131 (US 131). These former sections of the mainline highway, along with the necessary connecting roads, allow traffic to access the downtowns business districts of cities bypassed by sections of US 131 built since the 1950s. The extant business loops connect to Constantine, Three Rivers, Kalamazoo, Big Rapids, Cadillac, and Manton. The former bypass route in Grand Rapids allowed traffic to bypass that city's downtown at a time when US 131 still ran through the heart of the city, and the later business route connected through downtown while US 131 ran on a freeway bypassing the central business district.
US Highway 10 (US 10) is a part of the United States Numbered Highway System that runs from West Fargo, North Dakota, to the Lower Peninsula of the US state of Michigan. The highway enters Michigan on SS Badger, which crosses Lake Michigan between Manitowoc, Wisconsin, and Ludington. As the highway crosses the state, it is a two-lane undivided highway between Ludington and Farwell and a freeway from Farwell east to the highway's terminus in Bay City. US 10 runs concurrently with US 127 in the Clare area along a section of freeway that includes a welcome center in the median. Outside of the Clare and Midland areas, US 10 runs through rural areas of West and Central Michigan in a section of the Manistee National Forest as well as farmfields.
There have been seven business routes of US Highway 31 in the state of Michigan. All of the business routes are former sections of US Highway 31 (US 31). They connect the freeway mainline of US 31 to the various downtowns of cities bypassed by US 31. Two of the current business routes, for Hart and Ludington, are business spurs, connecting to US 31 on only one end, while the remainder for Muskegon, Whitehall–Montague and Pentwater, are business loops. The two former routes, for Niles and Holland were a business spur and loop, respectively.
M-56 was a state trunkline highway in the southeastern part of the US state of Michigan. It existed from 1919 until 1957. The highway ran north from Monroe, where it connected with US Highway 24, to Flat Rock where it terminated at an intersection with US 24/US 25. Before a series of truncations in the 1950s, the highway continued along the Huron River to New Boston and Belleville. The trunkline was progressively scaled back to Flat Rock before being decommissioned in 1957.
US 31 near New Era 
