Isle Royale /ˌaɪl ˈrɔɪ.əl/ is an island of the Great Lakes, located in the northwest of Lake Superior, and part of the U.S. state of Michigan. The island and the 450 surrounding smaller islands and waters make up Isle Royale National Park.

The island is 45 miles (72 km) long and 9 miles (14 km) wide, with an area of 206.73 square miles (535.43 km), making it the largest natural island in Lake Superior, the second largest island in the Great Lakes (after Manitoulin Island), the third largest in the contiguous United States (after Long Island and Padre Island), and the 33rd largest island in the United States. It is defined by the United States Census Bureau as Census Tract 9603 of Keweenaw County, Michigan. As of the 2000 census there was no permanent population. After the island was made a national park, some existing residents were allowed to stay, and a few leases are still in effect. Ferries from Michigan and Minnesota land at Rock Harbor on the eastern end of the island; this has a lodge, campground, and information center. Ferries from Minnesota also run to Windigo on the western end, which has a visitor center and campground.