DrewE wrote:
It's not really nearby to Illinois, at least not for most normal people, but Letchworth State Park in western NY state is probably the nicest state park I've had the pleasure of camping in so far. The campground itself is good but not great, but the scenery throughout the park and general ambiance of the place is spectacular. Plenty of hiking to keep (most) busy for a week or two.
I agree that letchworth is beautiful. Most sites are electric only, but bathrooms with hot showers.
If you decide to go as far as Letchworth, you might want to spend a couple of days at my favorite state park among the hundreds that I've visited. Ricketts Glen in PA isn't too far from Letchworth (about 3 hours), has two campgrounds (dry, but bathrooms & hot showers). The feature that makes it my favorite park is the stream that runs from the lake. 22 waterfalls along 5 miles or so of trail. All along the trail hundreds of cascades. While Fall is the most beautiful time to visit, the stream runs year round.
Some photos.