285 (2016 population: 539) is a rural municipality (RM) in the Canadian province of Saskatchewan within Census Division No.

The eastern boundary of the RM runs along the South Saskatchewan River with the south-east corner at Gardiner Dam on Lake Diefenbaker.

On the RM's eastern boundary, and the western bank of the South Saskatchewan River, is Coldwell Park Recreation Site (51°18′35″N 106°56′07″W / 51.3098°N 106.9353°W / 51.3098; -106.9353).

[7][8] In the 2021 Census of Population conducted by Statistics Canada, the RM of Fertile Valley No.

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