East Moline is a city in Rock Island County, Illinois, United States. The population was 21,374 at the 2020 census. East Moline is one of the …East Moline is a city in Rock Island County, Illinois, United States. The population was 21,374 at the 2020 census. East Moline is one of the Quad Cities at the confluence of the Rock and Mississippi rivers, along with neighboring Moline and Rock Island in Illinois and the cities of Davenport and Bettendorf in Iowa. As of 2011, the Quad Cities has a population estimate of 381,342.