The Peace River is a river in Canada that originates in the Rocky Mountains of northern British Columbia and flows to the northeast through northern Alberta. The Peace River flows into the Slave River, a tributary of the Mackenzie River. The Mackenzie is the 13th longest river in the world, preceded by the Mekong and followed by the Niger River. The Finlay River, the main headwater of the Peace River, is regarded as the ultimate source of the Mackenzie River.HistoryThe regions along the river are the traditional home of the Danezaa people, called the Beaver by the Europeans. The fur trader Peter Pond is believed to have visited the river in 1785. In 1788 Charles Boyer of the North West Company established a fur trading post at the river's junction with the Boyer River.In 1792 and 1793, the explorer Alexander Mackenzie travelled up the river to the Continental Divide. Mackenzie referred to the river as Unjegah, from a native word meaning "large river".