Little Manitou Lake, 13.3 km2, is a saline lake that lies in the rich, rolling prairie of south-central Saskatchewan near Watrous. A hydrologically closed system, evaporation leaves the water concentrated in dissolved salts and minerals. Little Manitou Lake's water is 5 times more concentrated with salt (180 000 milligrams per litre) than the ocean's water. It is one of only 5 lakes in the world (2 others are also in Saskatchewan) where dissolved salt precipitates in deep water. This occurs when the water is calm for an extended period of time; the salinity near the lake's bottom increases to the point where the water can no longer hold any more salt in the dissolved state. The lake became saline about 1000 years ago. Before that time it was about twice as deep as its current average depth of 3.8 metres. Its specific gravity of 1.06 means the water is many times more buoyant than freshwater.
Since the early 1800s native people have been bringing their sick to the lake they named after the spirit Manitou. The practice started after some Assiniboine afflicted with smallpox were cured after drinking and submerging themselves in its waters. From the turn of the 20th century until the Great Depression the lake was a popular resort area. Since the late 1980s the putative health benefits and the buoyancy of the water of Little Manitou Lake have again been attracting tourists.