Rivière-Mistassini (French pronunciation: [ʁivjɛʁ mistasini]) is an unorganized territory in the Canadian province of Quebec, located in the regional county municipality of Maria-Chapdelaine.

The territory had a population of 27 as of the Canada 2021 Census, and covered a land area of 17,629.74 km2.

The eponymous Mistassini River has its source in the far northern part of the territory and entirely bisects it from north to south.

Population trend:[4] Private dwellings occupied by usual residents: 16 (total dwellings: 20)

This Quebec location article is a stub.