Interstate 41 (I-41): Illinois Line to Green Bay, Miles and Crash Record

How long is I-41?

End to end, I-41 measures 175.00 miles in both Wikipedia and Interstate Guide. The January 2026 FHWA Route Log gives 176.97: 2.50 miles in Illinois and 174.47 in Wisconsin. Interstate Guide uses the same Illinois figure and 172.50 miles for Wisconsin, so the Route Log runs about 2 miles longer, all of it in Wisconsin. Wikipedia's exit list puts the state line only about 0.90 miles from the southern end.

On this route the Route Log rows keep the pavement I-41 shares with other Interstates. The overlap notes list 2.5 miles with I-94 in Illinois, and in Wisconsin 25.5 miles with I-94, 5 with I-43 and 10 with I-894, all between Russell and the Zoo Interchange in Milwaukee. Since those stretches already sit inside the 176.97 miles, the crash rates on this page use the Route Log rows as they are.

Where I-41 starts and ends

I-41 starts at the I-94 and US 41 interchange in Russell, Illinois, about a mile south of the Wisconsin line, where the Tri-State Tollway ends. It finishes at the interchange with I-43, US 41 and US 141 in Howard, near Green Bay. Interstate Guide places that end in neighboring Suamico.

By Wikipedia's mileposts, the first 32.6 miles follow I-94 through Kenosha and Racine counties to the Mitchell Interchange in Milwaukee. From there I-41 runs with I-894 to the Zoo Interchange, sharing a few miles with I-43 as far as the Hale Interchange, then follows US 45 northwest toward Richfield. Past Fond du Lac and Oshkosh it crosses Lake Butte des Morts on a causeway in Winnebago County, then goes on through Appleton and De Pere to Green Bay. Ten Wisconsin counties lie along the way, plus Lake County in Illinois.

Interstate junctions along I-41

The list starts in Illinois and runs north. I-41 begins on I-94 and stays on it across the state line, so I-94 shows up for both states. I-43 is listed twice: in Milwaukee, where the two routes share pavement between the Mitchell and Hale interchanges, and at the northern end in Howard, where I-41 stops at I-43. Between Milwaukee and Green Bay, I-41 crosses no other Interstate.

Fatal crashes on I-41

Fatal crashes on I-41 killed 54 people from 2020 to 2024, about 11 a year, in 49 crashes. Figured on the 176.97 Route Log miles, that comes to 6.1 deaths per 100 miles a year, below the 9.5 that the Interstate network averages. I-41 ranks 38th of 56 rated routes, where 1 is the highest rate. Deaths held at 13 a year from 2020 through 2022, then dropped to 9 in 2023 and 6 in 2024.

All 54 deaths were in Wisconsin, which has a rate of 6.2. Illinois recorded none, and its few miles are too short for a rate, so Wisconsin is the only state with one. Milwaukee County had the most deaths with 13, followed by Kenosha County with 8, Outagamie County around Appleton with 7, Washington County with 6 and Brown County around Green Bay with 5.

Counties with the most I-41 crash deaths

Bridges on I-41

The 2025 National Bridge Inventory lists 228 bridges on the I-41 main line, all in Wisconsin. Only 2 rate Poor, under 1 percent. Another 139 rate Good and 87 Fair. Half were built in 2011 or later. Of the main Interstates in our data, only I-42 and I-11 have a younger median.

Much of the road has been rebuilt since 2009. Winnebago County's 17 miles from WIS 26 to Breezewood Lane, including a new eight-lane Lake Butte des Morts Causeway, were rebuilt from 2009 to 2014, and Brown County's 14 miles from Orange Lane to Lineville Road from 2010 to 2017. In Milwaukee, the Zoo Interchange rebuild included 23 new bridges, and its ribbon cutting was on August 27, 2018.

Tolls on I-41

No toll facility on I-41 appears in FHWA's January 2023 inventory, and a trip from Russell to Green Bay pays no tolls. Drivers coming up from Chicago on I-94 pay on the Tri-State Tollway, which ends at the Russell interchange where I-41 begins.

How US 41 became I-41

The 2005 federal transportation bill, SAFETEA-LU, made US 41 from Milwaukee to Green Bay High Priority Corridor 57. An earlier House version called the corridor I-41, but the final law left the number out. WisDOT also weighed I-47, I-243, I-594 and I-643 before AASHTO chose 41 in November 2012, pending FHWA approval.

Weight-limit exceptions for the route came in H.R. 83, which became law on December 16, 2014. The designation took effect on April 7, 2015, and the first I-41 signs went up on the evening of May 29, 2015. Interstate Guide puts the resigning at about 3,200 signs and $5.9 million, finished in November 2015. Mileposts and exit numbers stayed the same as on the US 41 freeway.

The current big project is farther north. WisDOT began work in April 2024 to widen 23 miles between Appleton and De Pere from four to six lanes, due in 2030. Its new I-41 interchange at Southbridge Road, part of Brown County's South Bridge Connector over the Fox River, was completed in October 2026.

I-41 traffic and road conditions

Nearly every I-41 closure is a Wisconsin one, from work zones on the Appleton to De Pere widening to crashes in Milwaukee. The Wisconsin 511 link below covers nearly all of the route, and the Illinois link covers the short piece south of the state line.

I-41 questions