As covered in several earlier FreightWaves Classics articles, there are a number of highways designated as interstate highways that are located only in a single state. Examples include (with links to the articles): Interstate 2, Interstate 4, Interstate 11, Interstate 12, Interstate 14, Interstate 16, Interstate 17, Interstate 19, Interstate 27, and Interstate 37.
These and other highways are termed interstates and are part of the Interstate Highway System (IHS) because they were built to interstate standards. In addition, some of them may be extended into other states at some point in time.
I-43 serves Wisconsin only
Interstate 43 (I-43) is a relatively short interstate located solely in Wisconsin. It connects Green Bay to Milwaukee and then runs almost to Beloit on the Wisconsin-Illinois border. Its southern terminus is just outside of Beloit on its northeast side, where it merges into I 39 and I-90. Its northern terminus is located on the northern side of Green Bay, at the same junction where I-41 turns into Highway 41.
I-43 is primarily a north-south interstate, although the southern section from Milwaukee to Beloit runs diagonally across the lower part of the state in a northeastern-southwestern direction. I-43 is the 29th shortest interstate in the nation at 191.55 miles in length.
History of I-43
Considering its relatively short length, I-43 has a very complicated history.
The Wisconsin Transportation Commission knew that the IHS would be built at some point in time and commissioned studies of possible toll roads in the state. When the original IHS was approved by Congress in 1956, only two interstate highways were designated to be located in Wisconsin – I-90 and I-94. This led the Wisconsin Transportation Commission to request an additional interstate connecting Milwaukee to Green Bay. However, the federal government denied the request. Then the Wisconsin Turnpike Commission (which was established in 1953) submitted a request to the Federal Highway Administration in 1963 for a route that connected Milwaukee and Superior by way of Green Bay and other cities, and noted that the highway could be completed in increments. Only the Milwaukee-to-Green Bay segment was approved, however.
As noted above, Interstate 43 was not part of the original plan for the IHS as passed by Congress in 1956. Construction of what ultimately became I-43 was started in the early to mid-1960s (but again, not as I-43). The highway was commissioned in the 1970s along US 141 as part of the planned Milwaukee-Green Bay interstate highway that was approved in 1963. Government planning maps of the IHS from that time period showed what became I-43 as part of an extension of I-57. Potential funding legislation for the highway in 1972 also referenced the future interstate as an extension of I-57.
The initial 82-mile-long route for I-57 was approved by the Federal Highway Administration in May 1973. It was to run from Saukville, northeast along US 141, to WIS 42 and then northward to US 151. A northwesterly trajectory took I-57 from US 151 to south of Green Bay. The proposed new I-57 took it along the WIS 57 corridor into Milwaukee
The interstate highway that ran between Milwaukee and Green Bay was then designated as a distinct route (numbered Interstate 43) rather than an extension of I-57, and its southern terminus was located at the junction between interstates 94 and 794 in downtown Milwaukee. The existing US 141 in north Milwaukee became part of I-43; the interstate highway was then extended north toward Green Bay. Construction of this portion of I-43 was finished in 1981.
Further south, construction on what was originally designated as WIS 15 began in 1969 and was completed in 1976. More than 10 years later (on November 24, 1987), that segment was added to I-43. This added 72 miles to the interstate, extending it in a southwesterly direction to an intersection with I-90 near the state line. When I-39 was extended into Wisconsin on October 16, 1992, I-43 was then connected to I-39.
Overview of I-43 today
Because the information above may be confusing, the current configuration of I-43 connects the following communities in Wisconsin (from south to north): Beloit, Delavan, Milwaukee, Sheboygan, Manitowoc and Green Bay. The highway has junctions with I-39, I-90, I-894, I-794 and I-41 along its route.