Moline is a city located in Rock Island County, Illinois, United States. With a population of 43,977 in 2010, it is the largest city in Rock Island County. Moline is one of the Quad Cities, along with neighboring East Moline and Rock Island in Illinois and the cities of Davenport and Bettendorf in Iowa. The Quad Cities has a population estimate of 381,342. The city is the ninth-most populated city in Illinois outside of the Chicago Metropolitan Area.