Moline (mōlēnˈ) [key], city (1990 pop. 43,202), Rock Island co., NW Ill., on the Mississippi River, in a coal area; inc. 1848. It is a transportation and industrial center, and has been a major producer of farm machinery since the industrialist John Deere moved there in 1847. Other manufactures are elevators and industrial equipment. A military arsenal is nearby. Moline, with Rock Island and Davenport and Bettendorf, Iowa, is part of a regional economic unit called the Quad Cities.