Ohio OH is the only state without a rectangular flag.  It is based on the pennon used by the cavalry between 1862 and 1865 and was designed by John Eisenmann.  The blue triangle stands for Ohio's hills and valleys, and the red and white stripes for the state's roads and waterways.  The stars refer to the 13 original states and four more show that Ohio was the 17th state to join the Union.   The white "O" in the triangle could stand for Ohio, or for the Northwest Territory, from which Ohio was formed, and the red inner circle could also represent the "O" of Ohio as well as the fruit of Ohio's most famous tree, the buckeye.  Ohio State Flag Adopted:  1902