Charles City is a city in and the county seat of Floyd County, Iowa, United States. Charles City is a significant commercial and transportation center for the area. U.S. Routes 18 and 218, Iowa Highway 14, and the Canadian National and Canadian Pacific railroads serve the city. The population was 7,396 at the time of the 2020 census, a decrease of 5.3%, from 7,812 in 2000.