Deep River, Ont, incorporated as a town in 1959, population 4193 (2011c), 4216 (2006c). The Town of Deep River is located in eastern Ontario, 208 km northwest of Ottawa. It is on the section of the OTTAWA RIVER referred to as La Rivière Creuse (the Deep River) by 17th-century French explorers and which later was at the heart of Canada's 19th-century TIMBER TRADE.