The Quad Cities are located in Illinois and which neighboring state?

The Quad Cities is a region of the American Midwest consisting of five cities located on the banks of the Mississippi River. These are the Illinois cities of Rock Island, Moline, and East Moline, and the Iowa cities of Davenport and Bettendorf.

Urban settlements in the area began in the 1830s to aid riverboat traffic through a treacherous stretch of rapids known as the "Rock Island Rapids.". Riverboat captains would frequently stop prior to these rapids to both rest their crews and hire specialized pilots who could navigate these hazardous waters ahead. Due to this need, the area developed a small, regional industry.

As the industrial revolution began to emerge in the U.S., many business leaders began looking at the Mississippi River as a source of power generation. The Quad Cities were widely seen as a promising foundation to build their companies. John Deere would be one such company.

After the American Civil War, due to their common economies and location, the cities of Davenport, Rock Island, and Moline began to form a common identity. By the time of the First World War, the three cities began to style themselves as the "Tri-Cities.". Growth in the region would continue to grow to the point where East Moline became a separate city, thus necessitating the new name of Quad Cities. The same would happen for Bettendorf in 1948. However, by this time the name "Quad Cities" had become firmly established; thus, future attempts to adopt "Quint Cities" never caught on.