Tobin Lake is a reservoir along the course of the Saskatchewan River in the Canadian province of Saskatchewan. Tobin Lake was formed by the building of the E.B. Campbell Dam on the Saskatchewan River in 1963. Tobin Lake is named for William Thorburn, who was a fur trader on the Saskatchewan River. He had built a trading post on the Saskatchewan River where it is met by the Petaigan River. The rapids near the post became known as the "Thornburn Rapids". The name was later shortened to "Tobin Rapids".

The Saskatchewan River is a major river in Canada. It stretches about 550 kilometres (340 mi) from where it is formed by the joining of the North Saskatchewan River and South Saskatchewan River just east of Prince Albert, Saskatchewan, to Lake Winnipeg. It flows roughly eastward across Saskatchewan and Manitoba to empty into Lake Winnipeg. Through its tributaries the North Saskatchewan and South Saskatchewan, its watershed encompasses much of the prairie regions of Canada, stretching westward to the Rocky Mountains in Alberta and north-western Montana in the United States.