I've been to the butterfly Expo few times now. It is located at The Irwin M. Krohn Conservatory is a conservatory located in Eden Park in Cincinnati, Ohio.
It’s a bit hot in most parts of the exhibit so bring plenty of water. Get there early few the best parking. And so its not too hot outside as well as inside because it is in June. It accessible for the most part.
Though, there are a few paths that you will get to the end of and have to turn around but that’s about it. I would recommend going to see it. It’s a pretty cool experience. Bring the kids. Watching them become amazed when they catch a butterfly on one of the paper flowers that you're given when you come in is awesome.