Storfosna is a populated island in the municipality of Ørland in Sør-Trøndelag county, Norway. It is located between Kråkvåg and Garten at the mouth of the Trondheimsfjord. The traditional district of Fosen is named after this island. There is a large deer population on the island. The island is connected to Kråkvåg by a causeway and bridge, and is connected to Garten (and the mainland) by a car ferry. The Storfosna Church is located on the island.