The Ohio state flag has a unique swallowtail pennant design (Ohio legislation describes the flag as "burgee-shaped" - all other state flags are rectangular). The flag was designed by John Eisemann and officially adopted in 1902.

The blue triangular field represents Ohio’s hills and valleys. It contains seventeen white stars - tthirteen stars surrounding the circle are symbols of the original thirteen colonies. Four stars at the apex of the triangle raise the total number of stars to seventeen (Ohio was the 17th state to enter the Union in 1803).

The red and white stripes represent the roads and waterways of the state. The white circle with a red center forms an "O" for "Ohio" and is also related to Ohio's nickname (The Buckeye State).