I-41 begins at the I-94/US 41 interchange in Russell, Illinois, located south of the Wisconsin–Illinois border at the end of the Tri-State Tollway. The highway continues north concurrently with I-94 to the Mitchell Interchange in Milwaukee, turns west to run concurrently with I-894 and I-43 to the Hale Interchange, and turns north to run concurrently with I-894 and US 45 to the Zoo Interchange, with the US 45 concurrency continuing until the I-41/US 41/US 45 split near Richfield. The Interstate roughly parallels I-43, which runs north–south along Lake Michigan from Milwaukee to Green Bay. I-41 runs through the Fox Valley and Green Bay, where it ends at the I-43 interchange. The Interstate is approximately long and located almost entirely within the state of Wisconsin, and is completely concurrent with a slightly adjusted alignment of US 41 to its termination in Green Bay.
History
The freeway portion of US 41 and US 45 from Milwaukee through the Fox Valley to Green Bay was proposed and designated as an Interstate Highway as part of the 2005 highway funding bill. In the initial language of the bill, the route was named Interstate 41, which correlates with the U.S. Highway it parallels and also complies with the Interstate naming guidelines through the American Association of State Highway and Transportation Officials. The final bill omitted the I-41 designation. In 2009, Green Bay officials began a campaign to have US 41 designated as a northern extension of I-55 from its current termination in Chicago, with the alternative being designated as a spur of I-43. At the spring meeting of the Special Committee on U.S. Route Numbers of AASHTO on May 18, 2012, the I-55 designation was discussed by the committee. Coordination would have been required with the Federal Highway Administration and the Illinois Department of Transportation on the I-55 designation. However, IDOT officials were not interested in signing an extension of I-55 from its Chicago terminus to the state line. Therefore, the Wisconsin Department of Transportation decided to seek a different designation not requiring the cooperation of their Illinois counterparts. Four designations were proposed by WisDOT and put up for public review: two new primary designations and two auxiliary designations. At the end of October 2012, WisDOT submitted I-41 to AASHTO for consideration at their fall Special Committee meeting, where it was conditionally approved on November 16, 2012, pending FHWA concurrence. Official approval of I-41 then hinged on weight limit exceptions being approved for the route, which initially passed the United States House of Representatives as H.R. 4745 and awaited a United States Senate vote as S. 2438, but were later passed in a different bill on December 16, 2014. On April 9, 2015, Wisconsin Governor Scott Walker announced that the FHWA had approved I-41 as part of the Interstate Highway System. According to WisDOT, the approval came two days earlier. WisDOT replaced or modified 3,500 signs before and near September 2015 after coordination with IDOT and the FHWA. Over the next 5–10 years, shoulders are slated to be rebuilt as older parts of the highway are upgraded. The re-designation to Interstate status also makes the route subject to the Highway Beautification Act, meaning current advertising billboards along the Milwaukee to Green Bay portion of the road can no longer be upgraded or enlarged, nor can new signs be added.
