US 6 crosses the I-74 Bridge from Bettendorf, Iowa, south into Moline, concurrent with Interstate 74 (I-74).

It intersects I-80 as it leaves the Quad Cities area and closely parallels I-80 for the rest of its length in Illinois.

Two blocks north of leaving US 30, US 6 intersects the southern terminus of IL 171 and turns east onto Maple Road.

[3][4] In 1934, both portions were changed to its current routing, from Princeton to Spring Valley and in Lockport.

[5][6][7] By 1953, the route was rerouted to travel along Torrence Avenue and part of the Kingery Expressway (from US 30 Alternate to Indiana state line).