[2] A parcel of land of about 2,500 acres (10 km2) was reserved as a breeding ground,[5] encompassing the northernmost 27 kilometres (17 mi) of the lake's shoreline.

[6] In 1917, it was officially named Last Mountain Lake Bird Sanctuary, and was managed and operated by the Fish and Game League.

[6] Last Mountain Lake Bird Sanctuary is located in the northern mixed grasslands,[2] It is characterised by mud flats used by shorebirds and marshes used by waterfowl at the north end of the lake, whose water level is managed "within a series of basin" by control structures built by Ducks Unlimited Canada.

[2] The shoreline is primarily sandy, interspersed with rocky or gravelly tracts, and features numerous peninsulas forming bays between them.

[7] On 24 June 1987, the Last Mountain Lake Bird Sanctuary was officially recognized as a National Historic Site of Canada.

[3] Among the elements cited for the designation are undisturbed natural features, including the wetlands, water and shoreline, forest, and adjoining grasslands.