The Rural Municipality of Mossey River is a rural municipality (RM) in the Parkland Region of Manitoba, Canada, located at the south end of Lake Winnipegosis.

[3] The Rural Municipality of Mossey River was incorporated on May 1, 1906.

[3] On January 1, 2015, it amalgamated with the Village of Winnipegosis as dictated by The Municipal Amalgamations Act, which required that municipalities with a population less than 1,000 amalgamate with one or more neighbouring municipalities by 2015.

[4][1][5] The Government of Manitoba initiated these amalgamations in order for municipalities to meet the 1997 minimum population requirement of 1,000 to incorporate a municipality.

[6] In the 2021 Census of Population conducted by Statistics Canada, Mossey River had a population of 1,450 living in 612 of its 730 total private dwellings, a change of 26.6% from its 2016 population of 1,145.