This is a large park with multiple loops spread across an Upper and Lower campground.

The Lower Campground has nice views of the Mackinac Bridge and the Straits of Mackinac. 

Easy access off of I-75, but that means you will hear freeway traffic and all the trucks coming across the Mackinac Bridge's grates. 

Site size varies quite a bit so double-check it before booking if you have a big rig. Also, the campground roads are a bit narrow so maneuvering during the busy season will be tricky but it's manageable. 

Bathrooms in the Upper Campground are decent, the Lower Campground has newer bathrooms. 

It's nice that, given the number of sites here, that there is a dump station for Lower and one for Upper. 

If you can get by without electricity, check out the "A" sites in Lower Campground as they are right on the water. 

There's a nice trail through the woods between the Upper and Lower campgrounds and the nearby Father Marquette Memorial is worth checking out. The town of St. Ignace is cute with local shops and restaurants, plus the ferry dock to Mackinac Island. 

Cell service was decent for Verizon and Google Fi but seemed stronger in the Lower Campground. 

Note that if you stay in October, water is off and bathrooms are closed. Water is available at the ranger station and there are vault toilets. They do leave the electricity on at the sites.