In the U.S. state of Illinois, U.S. Route 41 runs north from the Indiana border beneath the Chicago Skyway on Indianapolis Boulevard to the Wisconsin border north of the northern terminus of the Tri-State Tollway with Interstate 94. It is the only north–south U.S. Route to travel through a significant portion of the city of Chicago, carrying Lake Shore Drive through the central portion of the city along the lakefront. U.S. 41 in Illinois is 64.81 miles (104.30 km) in length.

U.S. 41 enters Illinois concurrent with U.S. Routes 12 and 20 on the far southeast side of Chicago. They run together until the junction of 95th Street and Ewing Avenue. U.S. 41, now South Mackinaw Avenue, then zig-zags along other local South Chicago roads. From East 87th Street, South Burley Avenue, South Baker Avenue and South Shore Drive, U.S. 41 continues through South Shore Neighborhood's section of South Shore Drive before reaching the southern terminus of Lake Shore Drive.

The Lake Shore Drive section of U.S. 41 is a six-to-eight lane highway along the shores of Lake Michigan through Chicago's lakefront park system. It is a limited access highway except for five signalized intersections near downtown Chicago.

Just short of the northern terminus of Lake Shore Drive, U.S. 41 exits at Foster Avenue. It follows Foster Avenue west for over two miles (3 km) and then heads northwest on Lincoln Avenue into neighboring Lincolnwood. Between Lake Shore Drive and Lincolnwood, U.S. 41 intersects U.S. Route 14 twice; once at its terminus at Foster Avenue and Broadway, and once again at the intersection of Peterson Avenue and Lincoln Avenue.

U.S. 41 is named Skokie Boulevard through Skokie, then its name changes to Skokie Road north of Skokie. Traveling north, it joins Interstate 94 (Edens Expressway) westbound just north of the Old Orchard Shopping Center; they split a few miles north when U.S. 41 becomes the Skokie Highway. The highway serves as a major north–south arterial expressway for much of its routing through Chicago's northern suburbs, as well as an oft-used alternate for truckers avoiding the cost of tolls on the Tri-State Tollway. Before reaching the Wisconsin border, U.S. 41 rejoins Interstate 94 at the northern terminus of the Tri-State Tollway; these two roads continue, toll-free, north 1 mile (2 km) to the Wisconsin border.

"Google Maps from Park Avenue West to the I-94 intersection near the Wisconsin border"