We tent camped at Foss State Park in August 2020. We stayed at the Cottonwood campground site #6. All the tent sites were very spacious. There was a picnic table and grill and a water faucet nearby. The sites were nice and grassy and mowed. The bathroom was nice and clean with individual showers, each with their own door. So they were nice and private. Some of the old reviews mention needing quarters for the showers but they are now free. The playground was new and the kids had fun playing on it. The RV spots were a little crowded on the backside of the campground but pretty spread out closer to the entrance.
We drove through the Sandy Beach campground and it seemed nice and secluded but the picnic tables were a little run down. The playground was really old too. But I think the bathroom was newer. Also, there was no sandy beach in this area. 🧐
The swim beach was nice and sandy. Much better than a lot of Oklahoma lakes. But like most lakes in Oklahoma, the water was super muddy.
There are two cabins for rent here. They looked pretty new as well. They have a marina and I believe you can rent boats but we never checked it out.
Overall, I definitely recommend Foss. It was a nice family friendly park to visit.