The State Trunkline Highway System of the US state of Michigan is a network of roads owned and maintained by the Michigan Department of Transportation (MDOT). The most prominent of these roads are part of one of three numbered highway systems in Michigan: Interstates Highways, US Highways, and the other State Trunklines. Other systems of roads are operated by the 83 counties in the state as well as each city.
Interstate Highways and US Highways are assigned at the national level. Interstate Highways are numbered in a grid—even-numbered routes are east–west routes (but the lowest numbers are along Mexico and the Gulf of Mexico), and odd-numbered routes are north–south routes (with the lowest numbers along the Pacific Ocean). US Highways are also numbered in a grid—even numbered for east–west routes (with the lowest numbers along Canada) and odd numbered for north–south routes (with the lowest numbers along the Atlantic Ocean). For this reason, mainline (two-digit) Interstate Highways in Michigan all have numbers above 69 and mainline US Highways all have numbers below 45. Three-digit Interstate and U.S. Highways, also known as "child routes," are branches off their main one- or two-digit "parents". The Interstate and US Highways are maintained by MDOT. Interstate 75 (I-75) and US Highway 23 (US 23) are the longest examples in the state.
State Trunklines are the other state highways maintained by MDOT. These highways are completely owned and maintained by the state. Michigan highways are properly referred to using the M and never as "Route 28" or "Highway 115", but as M-28 or M-115. The marker used for state trunklines is a diamond with a block-letter "M" at the top. Roads that are maintained by the state but not assigned a state trunkline designation carry an unsigned highway designation.
County-Designated Highways are assigned numbers in a zone system by MDOT, but maintained by the counties. Each zone is indicated by a letter A–H which is followed by a number based on a grid inside that zone. Each county also maintains any other roadway that is not a state trunkline or a city street. The numbering and signing practices vary from county to county, as does the size of each county's system. Numerical designations typically do not carry over from one county to the next; a CDH that crosses county lines keeps its designation in each county however. County road designations are typically abbreviated "CR" or "Co Rd" followed by the number, and CDHs are abbreviated to just their letter and number assignment.
M-119 is a 271⁄2-mile-long (44.3 km) state trunkline highway entirely within Emmet County. The highway follows the shore of Lake Michigan and the Little Traverse Bay, with its southern terminus at US 31 near Bay View, about four miles (6.4 km) east of Petoskey; the northern terminus is at a junction with county roads C-66 and C-77 in Cross Village. North of Harbor Springs, the highway is known as the Tunnel of Trees Scenic Heritage Route. This section of highway lacks a centerline and is known for its scenic beauty. On an average day, between 2,000 and 15,000 vehicles use various parts of the highway. The first highways along the route of the modern M-119 was a section of the original M-13 designated by July 1, 1919. This highway was later redesignated M-131 in late 1926, a designation it held until 1979. During this timeframe, another highway bore the M-119 moniker in the southern part of the state near Paw Paw from the 1930s until the early 1970s. In between 1926 and 1979, M-131 was extended and truncated on both its northern and southern ends at various times. Since the M-119 designation was applied to the current highway, no changes have been made to the routing. (more...)