Peace River (Traditional Chinese: 和平河; French: Rivière de la Paix) is a river in eastern Gravenhurst Region. The headwaters of the river is located in the Wellington Highlands in the southern limits of the City of Vandehogan. It then follows a north-south path and flows through the Town of Wellington and the City of Lisi, finally emptying into Lake Haldimond. The river acts as a municipal boundary between Lisi and Donsley near Williamson. The river is also the reason why Williamson is nicknamed "The Peace Village".
The Peace River Expressway generally follows the river's alignment while running in the City of Lisi.
There goes a local hymn in the Lisi CMA called the Peace River Hymn, and the lyrics as follows:
- Peace is flowing like a river, flowing out of you and me. Flowing out into the desert, setting all the captives free.
It is unclear whether this hymn has anything to do with the river, nor the exact origin of the hymn is known.