Ballyhoura ACTIVE Summer Series. While it's described as a trail race, it is in reality mostly on narrow roads and paths within Doneraile Park. It would be wrong to think that it's some sort of cross country race and that you need to run through mud or long grass.
As for Doneraile Park itself, it really is a lovely spot. It's basically an old country estate and is now a grassland park with some small forested areas.