Deep Lake Unit is a wonderful rustic campground at Yankee Springs Recreational Area. We thoroughly enjoyed camping here. Site D70 was very nice and overlooked the lake from atop a hill and through a few trees. Many trails to walk and a trail directly from your campsite will lead along the water to the boat launch and fishing pier only about a 10 minute walk away. Mosquitos were not bad for mid-June but wear bug spray as we did find one deer tick on us (don't let that discourage!). Very friendly park staff always willing to give good suggestions on trails to hike or bike, or where the fish are biting. We will definitely return to camp here. Much more relaxed and in with nature than the modern sites, although equally nice in amenities if that's what you're looking for. Fun beach and water slide over at Gun Lake (still in same park), only a short 10 minute car ride away. A+++ Michigan State Park!