Rock Island, Wisconsin, is just north of Washington Island.
It is a state park and is geologically part of the Niagara Escarpement.
I hiked around Rock Island in June...
Boat house on Rock Island
Interior of boathouse
A large portion of the island was once owned by a wealthy inventor, Chester Thordarson, who made his fortune in the early 1900s creating generators and other things to handle and transmit electricity. He had this lovely boathouse built from limestone on the island.
Limestone on the island
Thousands of forget-me-nots bloom on the island
Columbine in bloom