Not a dome, but a cupola.One of the Ohio Statehouse's most distinctive exterior features is the low, conical roof atop the two-story cupola, positioned where many viewers expect to see a dome. In the long span between beginning construction on the Statehouse and its completion, the "finished" design changed many times and various proposals included a round dome atop the building. Isaiah Rogers, a well-known Cincinnati architect, was recruited to supervise the final stages of the Statehouse's construction in the late 1850s. During his tenure, Rogers oversaw completion of the building's interior and coordinated work on the distinctive rotunda and its enclosing cupola. Rogers, in deciding not to use a dome, was actually reverting to a design scheme by two earlier architects who worked on the Statehouse project in 1848. In the end, the building featured a two-story drum with a low conical roof called a cupola. The cupola drum high atop the Ohio Statehouse is 70 feet tall and 75 feet across. The height of the building from ground to the top of the pinnacle of the cupola is 158 feet, the height of a modern 13-story building.

If the link doesn't work on this webpage, please visit
http://www.ohiochannel.org/embed/133124

To view a virtual tour of the Ohio Statehouse Cupola (25:50 minutes), please visit
https://www.youtube.com/watch?v=bxQC_xqs5TE