The Quad Cities is a region of five cities in the U.S. states of Iowa and Illinois: Davenport and Bettendorf in southeastern Iowa, and Rock Island, Moline, and East Moline in northwestern Illinois. These cities are the center of the Quad Cities metropolitan area, a region within the Mississippi River Valley, which as of 2023, had a population estimate of 467,817 and a Combined Statistical Area (CSA) population of 474,019, making it the 90th-largest CSA in the nation.