St. Mary's Alpine Provincial Park, Provincial park in East Kootenay, Canada

St. Mary's Alpine Provincial Park features granite cliffs, alpine lakes, tundra-like terrain, and forested valleys across a large section of the Purcell Mountains. The park is cut through by seven creeks that feed multiple lakes and form waterfalls dropping down steep rock faces.

The park was officially designated in 1973 as a protected area for its alpine environment and to allow outdoor recreation. This formal protection came after decades of growing interest in preserving these remote mountain landscapes.

The park lies within the traditional territory of the Ktunaxa First Nation. The name St. Mary's was given by later settlers; the Ktunaxa know the surrounding East Kootenay highlands through their own place names and travel routes. Today the land is visited almost only by backcountry travellers, and no settlements stand nearby.

Access to the park is through forest service roads connected to Highways 3 and 3A, with the main route going from Dewar Creek to Mortar Lake. Road conditions change with the seasons, so checking conditions beforehand helps with planning your visit.

Seven creeks drain the park's lakes, and some of the resulting cataracts fall as much as 150 metres. The Ministry of the Environment advises that hikers reach this protected area only by bushwhacking and route finding, so few people are encountered there.