Big X
As I-80 and US 6 approach the Quad Cities metropolitan area, the speed limit drops to for the final time. Just within the city limits of Davenport is the I-280 interchange. US 6 exits to the south to join I-280 while I-80 is joined by US 61. I-80 and US 61 only share of freeway before US 61 exits to its own freeway heading north. In between the two exits is an interchange with Northwest Boulevard, which marks the eastern end of Iowa 130. A couple miles east of the eastern US 61 interchange is the western end of I-74. Because of a "turn off to stay on" interchange with I-74 and I-280 near Colona, Illinois, called "the Big X", I-74 through traffic is urged to use I-80 around the Quad Cities to the Big X. At the Big X, traffic from both I-74 and I-80 must exit their respective freeways to continue on the same route. Near the Mississippi River, the Interstate takes a sharp curve to the southeast to line up perpendicularly to the river. Just before the base of the bridge is an interchange with US 67, the last exit in Iowa. I-80 ends its journey through Iowa over the Mississippi River on the Fred Schwengel Memorial Bridge. It enters rural Rock Island County, Illinois, and continues towards Chicago.