Stopped by the Castle Rock on the way back from Soo Locks.
To get to the top of Castle Rock be ready to climb 171 steps, and it is a STEEP climb. Trust me by the time you will get there, you will be out of breath. The view from the top is amazing.
Entry fee is $1 but free if you have the Michigan Recreation Pass. You just need to show them a photo of your license plate. There is a very large gift shop where you can buy souvenirs of not just Castle Rock but also the area around (Mackinac Island, Mackinaw City, Mackinac Bridge, and Upper Peninsula). We found the prices here were cheaper than shops in Mackinac Island but Mackinac Island definitely had more variety.
Also, unsure why there is a statue of Paul Bunyan and his mythical blue Ox. Am sure there is a connection that I don’t know about.