Interstate and U.S. highways The state of Wisconsin is served by eight
Interstate Highways, consisting of five
primary routes and three
auxiliary routes. The first part of this system was constructed in 1956, and its most recent expansion took place in 2015, with the addition of
I-41 to the system. Wisconsin's longest Interstate Highway is
I-94, at , and its shortest is
I-535, which extends only into the state. There are also fourteen
United States Numbered Highways in the state of Wisconsin, which were designated beginning in 1926 and ending in the mid-1930s. The routes of the U.S. Highway System in Wisconsin have remained essentially unchanged since
U.S. Highway 16 became a state highway in 1978. There are also several
business routes, usually maintained by local governments.
State trunk highways The state of Wisconsin maintains 153 state trunk highways, ranging from two-lane rural roads to limited-access freeways. These highways are paid for by the state's Transportation Fund, which is considered unique among state highway funds because it is kept entirely separate from the general fund, therefore, revenues received from transportation services are required to be used on transportation. The majority of state highway funding comes from gas taxes and vehicle registration fees.
Other state highways WisDOT also develops and maintains some minor routes, under the designations of
Scenic Byways and
Rustic Roads. Scenic Byways are minor roads, typically two-lanes, that travel through areas of "scenic and historic interest." Rustic Roads are lightly traveled local roads, sometimes paved and sometimes dirt or gravel, whose rustic characteristics are intentionally maintained and preserved by WisDOT.
Other highways in Wisconsin All
72 counties in Wisconsin maintain their own system of
county highways, which are usually small, have low levels of traffic, and terminate at the limits of cities and towns. Each highway is designated with a label of between one and three letters, and are usually named sequentially, starting with Highway A and continuing to Z, then using double letters from AA to ZZ, and using triple letters if necessary, although this is not a requirement and there are plenty of exceptions. The various cities, towns, and villages of the state each maintain their own roads beyond this, servicing individual homes and businesses and connecting them to the other systems, although these are not typically referred to as highways. There are also several types and systems of roads in Wisconsin that are not part of any state or local highway system, and are not specifically constructed or maintained by the state Department of Transportation or by any local agency. •
Forest Highways are routes through
National Forests, and are thus designated by the
United States Forest Service. • The
Kettle Moraine Scenic Drive is a marked route that follows county and local roads past historical markers and attractions in the
Kettle Moraine. It extends between
Whitewater and
Elkhart Lake. • The
Lake Michigan Circle Tour and the
Lake Superior Circle Tour encircle
Lake Michigan and
Lake Superior, respectively. •
Minnesota State Highway 23 passes through Wisconsin in
Douglas County for about before returning to Minnesota. • The
Yellowstone Trail was the first transcontinental automobile highway to be constructed through the upper tier of states in the United States. It was exempted from a state law banning privately designated highways in 1917. ==History==