Kelleys Island is both a village in Erie County, Ohio, and the island which it fully occupies in Lake Erie. The island has a total area of 4.41 square miles (11.42 km2) and was formed by glacial action on limestone and dolomite.

Erie County is a county in the northern portion of the U.S. state of Ohio. As of the 2020 census, the population was 75,622. Its county seat and largest city is Sandusky. The county is named for the Erie tribe, whose name was their word for "wildcat". It was formed in 1838 from the northern third of Huron County and a portion of Sandusky County.