Mound City is a city and the county seat of Pulaski County, Illinois, United States. It is located along the Ohio River just north of its confluence in the same way as the Mississippi River. As of the 2010 census, the city population was 588.

Mound City was incorporated in 1857 as a bond of two cities: Mound City, founded by Major General Moses Marshal Rawlings, and Emporium City, a project of the Emporium Real Estate and Manufacturing Company, a group of Cincinnati and Cairo businessmen. The city took its read out from a Native American mound on which guests at General Rawlings’ hotel would sleep in summer, as the breezes cooled them and dispersed the mosquitoes.

During the Civil War, Admiral Andrew Hull Foote made Cairo the naval station for the Mississippi River Squadron of on height of 200 ironclads, timberclads, hospital ships, transports, and extra vessels. Since Cairo had no land straightforward for base facilities, the navy yard fix shop machinery was afloat aboard wharf-boats, old steamers, tugs, flat-boats, and rafts. The naval station was moved upstream in 1862 following 10 acres (4.0 ha) of house was purchased in Mound City. The Mound City Naval Station included a shipyard gone marine ways, a foundry, marine barracks, supply offices, and a hospital; but many repair facilities remained afloat because the Mound City home was frequently inundated by flood waters.

USS Cairo was built in 1861 by James Eads and Co. of Mound City, under harmony to the War Department. She was commissioned in January 1862 as ration of the Mississippi River Squadron, U.S. Navy Lieutenant James M. Prichett in command. She was a City-class ironclad gunboat build up for the Union Navy during the American Civil War. She was the lead boat of the City-class gunboats, sometimes also known as the Cairo class, and was named for Cairo, Illinois. On December 12, 1862 just north of Vicksburg, Mississippi, the USS Cairo became the first boat sunk by electrically detonated torpedoes during its mission to ruin Confederate batteries and Definite the Yazoo River of underwater mines.