The Moon River is a river in the municipalities of Georgian Bay and Muskoka Lakes, District Municipality of Muskoka in Central Ontario, Canada. It flows from Lake Muskoka at the community of Bala to Georgian Bay, Lake Huron, south of Parry Sound. The name of the river is thought to be derived from its Ojibwa name moonz-ziibi, which means "moose river".

Lake Muskoka is located between Port Carling and Gravenhurst, Ontario, Canada. The lake is surrounded by many cottages. The lake is primarily within the boundary of the Township of Muskoka Lakes, the southeast corner is within the boundary of the Town of Gravenhurst and another small portion around the mouth of the Muskoka River is within the boundary of the Town of Bracebridge. The town of Bala is located on the southwest shores of the lake, where the Moon River starts. Lake Muskoka is connected to Lake Rosseau through the Indian River and lock system at Port Carling. The lake is mainly fed by the Muskoka River, Lake Joseph and Lake Rosseau.