M-185 is a state highway in the U.S. state of Michigan. It circles Mackinac Island. Mackinac Island is a popular tourist place on the Lake Huron side of the Straits of Mackinac. The highway is along the island's coast. The highway is a thin paved road that is long. There are scenic views of the straits that divide the Upper and the Lower peninsulas of Michigan. It also has views of Lakes Huron and Michigan. It doesn't connect to any other Michigan state highways. This is because it is on an island. People can only get to it by passenger ferry.