Old Wives Lake is a large, shallow endorheic salt lake in south-central Saskatchewan, located approximately 30 kilometres southwest of Moose Jaw and just north of the town of Mossbank. It is the second largest saline lake in Canada and fourth largest in North America, with a catchment area of 16,850 square kilometres and a surface elevation of 663 metres. The lake has no outflow, is fed primarily by the Wood River, and its shallow, relatively flat basin produces significant mudflats during seasonal water fluctuations. Two islands sit within the lake: the Isle of Bays and Sand Bar Island.

The lake is accessible from Highway 363, and the Old Wives Lake Nature Area along the south shore includes a boat launch near Mossbank. The nature area also features a 2.4-kilometre self-guided walking trail, a lookout deck, double viewfinders, a gazebo, picnic areas, and an outhouse — amenities that can serve paddlers before or after time on the water.

Because Old Wives Lake is a Federal Migratory Bird Sanctuary, established in 1925, paddlers should be aware that regulations governing the sanctuary apply to the area. The lake, together with Reed Lake and Chaplin Lake, forms a site of hemispheric importance within the Western Hemisphere Shorebird Reserve Network, designated in April 1997. The Isle of Bays Wildlife Refuge occupies the northeastern portion of the lake and provides protected nesting habitat for American white pelican, great blue heron, black-crowned night heron, double-crested cormorant, western grebe, California gull, ring-billed gull, and common tern. Spring and fall bring large concentrations of ducks, Canada geese, white-fronted geese, snow geese, and tundra swans, as well as approximately 500,000 migrating shorebirds including American avocet, marbled godwit, Wilson's phalarope, and semi-palmated sandpiper.

The lake's saline character — a product of its endorheic basin and glacial origins dating to roughly 20,000 years ago — means water quality differs substantially from freshwater lakes. The high salinity supports brine shrimp, which in turn drive the extraordinary concentrations of migratory birds. Paddlers should factor in the shallow depth and potential for extensive mudflats when planning access and routes, particularly during drier periods when water levels may be lower.