My wife and I camped at Cunningham Falls in June of 2012. Cunningham Falls actually has two separate camping areas. The Manor area is on Hwy 15 about 20 minutes north of Frederick, MD at the base of the Catoctin Mountains. On the other side of the mountaintop is the William Houck camping area. The two are not far from each other as the crow flies but there is no direct road between them. You have to drive about 15 minutes around the mountain to get from one to the other.
We camped in the Manor area. The sites are very wooded and spaced far apart it is mainly non-electric and is overall more suited to quiet, nature camping. You can hear Hwy 15 when it is quiet but the noise is not loud or annoying. At the entrance there is a nice nature center and a small shelter for indigenous birds of prey that have been injured and have to be cared for to survive. The restrooms are pretty nice with showers and were cleaned daily but not as thoroughly as we would have liked.
We drove around the mountain to check out the William Houck area. This area is more popular overall. You could say more "upscale". There are 3 or four loops going up the side of the mountain. They are closer together and aside for one of the loops, have more electric sites.
Before you reach the Houck sites, you pass a great little lake with a nice beach, picnic areas, and concession stand. The beach is very popular on the summer weekends so go there early if you want to get a parking spot. Just above the lake are a couple of trails (difficult and easy)that lead to the Falls.
We hiked to the falls one day and spent a couple hours at the beach on another day. There were a lot of people but everyone was nice and seemed to be having a good time. I would say that the Houck area is more suited to social campers and young families. The Manor area is for those who want to get away and be more to themselves.
Overall, we had a great time!