Susquehannock Campground

Gorgeous site on the lake. $20 for tents, $20-25 for rvs, available first come first served if not reserved. Only services provided are potable water at the main gate AT THE TOP, and vault toilets, but apparently you can use other services like showers at the nearby 7 points COE campground and there's a marina pretty close by. There are also nearby hiking and renowned biking trails.
This year they've revised the campground so that some sites that were previously allowing small RVs are now tent sites only. Otherwise, seems to be appropriate only for smaller RVs or small trailers. Super steep drop from the gate down two miles to the lake, with harsh speed bumps, so I had to really take it slowly even with my small pop up camper. I'm from the West so it was a real bonus to see some lightning bugs in early June there. :-)