In 1953, the Ohio Legislature designated the Ohio Buckeye, Aesculus glabra, as Ohio’s official state tree. The buckeye tree has also provided Ohioans with their principal nickname—the Buckeyes. Ohioans have referred to themselves as Buckeyes since at least the election of 1840 when Ohio resident William Henry Harrison won the presidency. The buckeye has become better known as The Ohio State University’s nickname, personified through their mascot “Brutus the Buckeye.”

Source: Ohio Secretary of State