This is an old-fashion county fair with all the associated trappings, animal smells, country kitch, a midway with rides that shoudl probably be condemed and fair-food. If you're not into that old-fashioned stuff, DON'T GO. Personally, I grew up in the deep South and fondly remember county fairs. I enjoy the smells and sounds (still won't ride the midway rides <grin>) and the food is great. It takes me back to my childhood and that's exactly why I go!
One downside to this fair - it is hosted in August, the hottest month of the year in the DC area. The fairgrounds are largely concrete and only a few areas are shaded. Bring a hat, sunscreen and hydration (or be prepared to buy a lot of drinks).
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.