Only stay if Ontonagon County Park is all that's left
Ontonagon County Park is right on Lake Gogebic. If that is all you read you might book a site. This place doesn't look like it has been updated in years. It is run down.
The positive is that it is right on the lake and has a boat ramp. So if you want to boat and can't find another place to camp on the lake, this will work for you. Otherwise I would head down the road a couple of more miles and stay at Lake Gogebic State Park or find a private campground on the lake.