Stephenson Island (formerly "Stephenson Isle") is located in the Menominee River within the boundary of Marinette, Wisconsin at a latitude of 45.1019294 north and longitude 87.6292735 west, at an elevation of 587 feet. It is named after Isaac Stephenson, a prominent politician and lumberman in Marinette at the turn of the 20th century. The island is operated as a city park and is uninhabited.