My wife and I camped at Janes Island State Park this past September.
The campground is right along the Chesapeake Bay. Across a narrow strip of water is the island. It is mostly made up of tall water grass but parts of it are wooded and accessible by foot. The foot trails are not the main attraction, it is the water trails. Campers and visitors can kayak, canoe, and run small powered craft through miles of natural canals that run into and through the island. A main canal through the middle leads you to a 5 mile long beach facing the bay. A large dock is available for docking and rentals.
Fishing is also good. We both caught Rock Bass and Sea Trout while trolling lures behind our kayaks.
The restrooms are modern and kept reasonably clean. The sites are fairly close together but it didn`t seem crowded. There is a large camp store with concessions near the dock. Tall pine trees keep the grounds shaded. All the campground employees and rangers were friendly and helpful.
We heard that mosquitoes and flies can be bad during the summer months but in late September they were not a problem.
Overall, we had an excellent time at Janes Island and plan to be back again next year.