121 (2016 population: 470) is a rural municipality (RM) in the Canadian province of Saskatchewan within Census Division No.

[5] The black swallowtail (papilio polyxenes asterius), a species of special concern, makes its home in this area.

In the 2021 Census of Population conducted by Statistics Canada, the RM of Moosomin No.

121 is governed by an elected municipal council and an appointed administrator that meets on the second Thursday of every month.

[3] The reeve of the RM is David Moffatt while its administrator is Kendra Lawrence.