When the federal government was planning the Interstate Highway System in the 1950s, Wisconsin proposed that the WIS 57 corridor become the route of an interstate highway. The state wanted an interstate to connect Milwaukee and Green Bay, two of Wisconsin's largest cities. Their plan chose the WIS 57 route over the nearby US 41 and US 141 corridors; the state did not want the interstate's route to favor either the port cities of Manitowoc and Sheboygan or the inland cities of Appleton, Fond du Lac and Oshkosh. Wisconsin wanted to designate the highway as Interstate 57 to preserve the highway's number; while this numbering would have fit in the west–east Interstate number scheme, an Interstate 57 was already planned in Illinois and Missouri. The state's proposal was ultimately rejected, and Interstate 43 was built on the US 141 corridor along the lakeshore instead. The US 41 corridor eventually became Interstate 41 in 2015, providing interstate access to all the cities the WI 57 routing would not have favored.