166 (2016 population: 806) is a rural municipality (RM) in the Canadian province of Saskatchewan within Census Division No.

166 was originally incorporated as a rural municipality on December 13, 1909.

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

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

[4] The reeve of the RM is Harold Martens while its administrator is Dianne Hahn.