This 2,350-acre campground was well-maintained and is located on Madeline Island (the largest Apostle Island) on Lake Superior. 

You need to take a ferry to get there and I took Madeline Ferry and it was easy even with an RV.

Big Bay State Park does not allow dogs (pets) on the 1.5-mile long beach which was disappointing, however, there was another campground (Big Bay Town Park) on the Island that had a fabulous pet-friendly beach so I spent time there.  

There are several hiking trails and Big View Trail was scenic along Lake Superior.

Big Bay State Park experience video:
https://youtu.be/LHGZdC6y-A0