Bailey Island is an island in Casco Bay, and a part of the town of Harpswell, Maine. Its permanent population at the 2000 census was 400.
It was originally a Native American settlement, with the name of Newaggin. The Bailey Island Bridge, which spans Will's Gut and connects Bailey Island to Orr's Island, was completed in 1928. It is the only cribstone bridge in the world. The island has had a number of notable summer visitors.