Kuiu Island is an island in the Alexander Archipelago in southeastern Alaska. It lies between Kupreanof Island, to its east, and Baranof Island, to its west. The island is 105 km long, and 10 to 23 km wide. It is nearly cut in two by Affleck Canal. It has 1,936.16 km² of land area, making it the 15th largest island in the United States. The entire island is part of Tongas…Kuiu Island is an island in the Alexander Archipelago in southeastern Alaska. It lies between Kupreanof Island, to its east, and Baranof Island, to its west. The island is 105 km long, and 10 to 23 km wide. It is nearly cut in two by Affleck Canal. It has 1,936.16 km² of land area, making it the 15th largest island in the United States. The entire island is part of Tongass National Forest.