The Rural Municipality of Chesterfield No. 261 (2016 population: ) is a rural municipality (RM) in the Canadian province of Saskatchewan within Census Division No. 8 and Division No. 3.
The RM of Chesterfield No. 261 incorporated as a rural municipality on December 9, 1912.
The southern boundary of the RM is along the South Saskatchewan River. The largest lake is Cabri Lake and the Mantario Hills are found in the western part of the RM. Within the hills is the Mantario Hills (SK 047) Important Bird Area (IBA) of Canada, which is a significant staging area for Canadian geese and nesting area for the ferruginous hawk. The Mantario Wildlife Management Unit is also found within the hills.
The following urban municipalities are surrounded by the RM.
The following unincorporated communities are within the RM.
In the 2021 Census of Population conducted by Statistics Canada, the RM of Chesterfield No. 261 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 Chesterfield No. 261 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 Chesterfield No. 261 is governed by an elected municipal council and an appointed administrator that meets on the second Tuesday of every month.