Rock Island State Park is a state park of the state of Wisconsin, in the United States, located on Rock Island in Lake Michigan off the tip of the Door Peninsula. The only public transportation to the island is by the passenger ferry Karfi from Washington Island. However, there is mooring and dock space for people with their own boats, and during winter the island is accessible via snowmobile and foot traffic. No "wheeled vehicles" (cars, all-terrain vehicles, bicycles) are allowed to be brought onto the island by visitors, although park staff use them routinely.