The Rural Municipality of Big River No. 555 (2016 population: ) is a rural municipality (RM) in the Canadian province of Saskatchewan within Census Division No. 16 and Division No. 5.
The RM of Big River No. 555 incorporated as a rural municipality on October 1, 1977.
The following urban municipalities are surrounded by the RM.
The following unincorporated communities are located in the RM.
There are several provincial campgrounds and a regional park within the RM's boundaries. The eastern boundary of the RM of Big River borders Prince Albert National Park.
In the 2021 Census of Population conducted by Statistics Canada, the RM of Big River No. 555 had a population of living in of its total private dwellings, a change of from its 2016 population of . With a land area of , it had a population density of in 2021.
In the 2016 Census of Population, the RM of Big River No. 555 recorded a population of living in of its total private dwellings, a change from its 2011 population of . With a land area of , it had a population density of in 2016.
The RM of Big River No. 555 is governed by an elected municipal council and an appointed administrator that meets on the second Monday of every month. The Reeve of the RM is Clint Panter while its Administrator is Michael Yuzik. The RM's office is located in Big River.