Lambert Island is an island located within Thunder Bay on the north shore of Lake Superior adjacent to Amethyst Harbour and Amethyst Beach. It falls within the boundaries of McGregor Township, Ontario, a part of the Municipality of Shuniah, Ontario. It is a privately owned island developed by Lambert Island Ltd. and is connected to the mainland by a bridge maintained by the shareholders of the company. It enjoys the reputation of being an exclusive summer resort for affluent citizens of the city of Thunder Bay, Ontario.