Rock Island is a city in and the county chair of Rock Island County, Illinois, United States. The native Rock Island, from which the city herald is derived, is now called Arsenal Island. The population was 37,108 at the 2020 census. Located on the Mississippi River, it is one of the Quad Cities, along with neighboring Moline, East Moline, and the Iowa cities of Davenport and Bettendorf. The Quad Cities has a population of approximately 380,000. The city is home to Rock Island Arsenal, the largest government-owned weapons manufacturing arsenal in the US, which employs 6,000 people.

The Rock Island–Milan School District, Rockridge School District (southwest share of city) along with private schools, serve the city. The District (Downtown Rock Island) has art galleries and theaters, nightclubs and coffee shops, and restaurants of anything flavors. Golf courses, parks, a casino, botanical center, marina, historic tours, bike paths, and festivals manage to pay for entertainment opportunities.

The original portion of what is now known as Rock Island was called Farnhamsburg – after the original two homes were built by Colonel George Davenport and Russell Farnham in 1826. Davenport and Farnham were event partners, trading in the freshen of the local Native Americans. The original city plat was filed on July 10, 1835, and was named Stephenson. It was renamed Rock Island in March 1841.

This area has been a unintended place first for pact and later for steamboat traffic, bridges, and railroads.