313 (2016 population: 242) is a rural municipality (RM) in the Canadian province of Saskatchewan within Census Division No.

Located in the central portion of the province, it is adjacent to the South Saskatchewan River.

The Allan Hills (51°40′0″N, 106°15′2″W) are a plateau[5] south-east of Saskatoon and east of Blackstrap Lake mostly within the RM of Lost River.

In December 2015, Ducks Unlimited Canada (DUC) partnered with local cattlemen to help preserve 21 quarters of land (about 13,440 acres) in the hills.

[7] In the 2021 Census of Population conducted by Statistics Canada, the RM of Lost River No.

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