Until 1967, the Peace River had its origin in the Rocky Mountain Trench at the head of Finlay River. At Finlay Forks the Finlay and Parsnip rivers met to form the Peace River. From that point it flowed eastward 1,195 miles to empty into the Slave River. Today, Finlay Forks is under the waters of 640-square-mile Williston Lake and the Peace River is 70 miles shorter because tit begins at the W.A.C. Bennett Dam.
Forty percent of the 120,000 square mile Peace River watershed is still with the province of B.C.
The name "Peace" is a translation of the First Nations word "Unjigah" by which the river was known east of the Rockies. It is said the Cree and Beaver First Nations established a peace treaty on the banks of this river near the turn of the 19th century.
Gold was discovered in the river in 1861 but it wasn't until 1898 when Europeans began to settle in the B.C. portion of the Peace River district.