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 joins the Athabasca River in the Peace-Athabasca Delta to form the Slave River, a tributary of the Mackenzie River. The Finlay River, the main headwater of the Peace River, is regarded as the ultimate source of the Mackenzie River. The combined Finlay–Peace–Slave–Mackenzie river system is the 13th longest river system in the world. History The 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". The decades of hostilities between the Danezaa and the Cree, (in which the Cree dominated the Danezaa), ended in 1781 when a smallpox epidemic decimated the Cree. The Treaty of the Peace was celebrated by the smoking of a ceremonial pipe. The treaty made the Peace River a border, with the Danezaa to the North and the Cree to the South. In 1794, a fur trading post was built on the Peace River at Fort St. John; it was the first non-native settlement on the British Columbia mainland. Post-settlement The rich soils of the Peace River valley in Alberta have been producing wheat crops since the late 19th century. In the early 21st century, the BC Grain Producers Association was researching the productivity of wheat and other grain crops near Dawson Creek. The Peace River region is also an important centre of oil and natural gas production. There are also pulp and paper plants along the river in Alberta and British Columbia. The Peace River has two navigable sections, separated by the Vermilion Chutes, near Fort Vermilion. The first steam-powered vessel to navigate the Peace River was the Grahame, a Hudson's Bay Company vessel built at Fort Chipewyan, on Lake Athabasca. Brothers of the Oblate Order of Mary Immaculate built the St. Charles to navigate the upper reaches of the River, from Fort Vermilion to Hudson's Hope. Approximately a dozen vessels