Do they have year around camping?

State Park in Michigan has camp ground across the street year round so you can still enjoy the park

Yes. Water is turned off around the end of October, but electric stays on, and there is a spigot behind the ranger station to fill jugs for fresh water.

I would have to say one would need to check directly with the local State Park itself. I personally live five minutes away and have never taken the time to ask this question myself, or to look it up. As I frequently camp in Bay City. I do believe they allow year'round camping, but there will be zero amenities available. Unlike summer camping one has electrical and can fill up on water.

I don't believe it is year around but they do have camping right across the highway from the park. The camping isn't actually in the state park. At least not as far as I saw. The only camping, as I said, was right across the highway. They may be open.