Moline is a city located in Rock Island County, Illinois, United States. With a population of 42,985 in 2020, it is the largest city in Rock Island County. Moline is one of the Quad Cities at the confluence of the Rock and Mississippi rivers, along with neighboring East Moline and Rock Island in Illinois and the cities of Davenport and Bettendorf in Iowa. The Quad Cities had a population of 384,324 in 2020. The city is the ninth-most populous in Illinois outside the Chicago metropolitan area.

Rock Island County is a county located in the U.S. state of Illinois, bounded on the west by the Mississippi River. According to the 2020 census, it had a population of 144,672. Its county seat is Rock Island; its largest city is neighboring Moline. Rock Island County is one of the four counties that make up the Davenport-Moline-Rock Island, IA-IL Metropolitan Statistical Area.