I've looked and don't know of any. There is a race with a clinic coming up on August 22nd near Louisville in the Ohio River. Go to active.com and search for Ohio River Open Water Swim. You should find it.
That said, maybe we could start one. I don't know of any places that will tolerate it outside of maybe Brookville Lake in Indiana? Do you?
I do not. I have seen some people swimming across the Ohio from Covington but I believe they were drunk. There have been a couple of open water races in the area, did you attend any?
I did the Great Ohio River Swim last year (double-crossing from the Serpentine wall to Newport and back), but missed it this year. Did the Fat Rabbit races in Columbus this year and last. Two years ago, Fat Rabbit did one at Miami Whitewater which was great. Mostly, though, I train in the pool and then find the next nearest Open Water swims in Columbus, Chicago, or elsewhere.
I'll be doing the one near Louisville in a couple of weeks.
I would definitely recommend the Fat Rabbit races and the Great Ohio River Swim even for beginners. They've drawn people of all ages and abilities.