Antique Real Photo Postcard. Identified as the Magnetawan River in Ontario, Canada. Undivided back, postmarked 1907. Condition: This is an original photo postcard, not a copy or reproduction. It is in very good condition. Comments: The Magnetawan River is a long river in Parry Sound District, Ontario, Canada. The river flows 175 km from its source of Magnetawan Lake inside Algonquin Provincial Park to empty into Georgian Bay at the community of Britt on Byng Inlet. The name of the river means "swiftly flowing waters" in the Ojibwa language.