Fort Madison is a city and a county seat of Lee County, Iowa, United States along with Keokuk. Of Iowa's 99 counties, Lee County is the only one with two county seats. The population was 11,051 at the 2010 census. Located along the Mississippi River in the state's southeast corner, it lies between small bluffs along one of the widest portions of the river.
Fort Madison was founded at the location of the first U.S. military fort in the upper Mississippi region. A replica of the fort stands along the river. Sheaffer Pens were developed and made in Fort Madison for many years. The city is the location of the Iowa State Penitentiary—the state's maximum security prison for men. Fort Madison is the Mississippi river crossing and station stop for Amtrak's Southwest Chief. Fort Madison has the last remaining double swing-span bridge on the Mississippi River, the Fort Madison Toll Bridge.