Big Island is an island in Prince Edward County, Ontario, Canada. Approximately 9.5 kilometres (5+3⁄4 mi) in length and with a maximal width of three kilometres (two miles), it is located in the Bay of Quinte in Lake Ontario, between Belleville and Demorestville. It is accessed by a fixed causeway of 600 m (660 yd, or 3⁄8 mi) length which connects Big Island to the remainder of Prince Edward County. The island is within the former Township of Sophiasburgh and is the largest of all off-shore islands in Prince Edward County.[1]