Conference & Expo Center in Ohio. Located in beautiful Xenia, Ohio, the Greene County Expo Center is a modern, state-of-the-art international conference center. Conveniently nestled between Columbus, Cincinnati and Indianapolis, your attendees have easy access to three airports and plenty of affordable options to get to your event. The Greene County Expo Center is proud to be the home of Home of The Greene County Fair, the Great Ohio Toy Show, Vintage Market Days of Dayton Cincinnati, Dayton Hon