Bruny Island is a 362-square-kilometre (89,000-acre) island located off the south-eastern coast of Tasmania, Australia. The island is separated from the Tasmanian mainland by the D'Entrecasteaux Channel, and its east coast lies within the Tasman Sea. Storm Bay is located to the island's northeast. Both the island and the channel are named after French explorer Bruni d'Entrecasteaux. Its traditional Aboriginal name is lunawanna-allonah, which survives as the name of two island settlements, Alonnah and Lunawanna.