Mason City

City, seat (1855) of Cerro Gordo county, northern Iowa, U.S., along the Winnebago River, about 120 miles (195 km) north of Des Moines. The area was inhabited by Winnebago and Sioux peoples when Freemasons arrived to settle the site in 1853; its earlier names were Shibboleth, Masonic Grove, and Masonville before the present name was adopted. The city is underlain by deposits of clay and limestone,