Waterton Lakes National Park is a national park located in the southwest corner of Alberta, Canada, and borders Glacier National Park in Montana, USA. Waterton was Canada's fourth national park, formed in 1895 and named after Waterton Lake. The park contains 505 km² (203 mi²) of rugged mountains and wilderness.

In 1932, Waterton-Glacier International Peace Park was formed from Waterton and Glacier. This park symbolizes the bonds of peace and friendship between the people of the United States and Canada, and a border crossing is open in the park during the summer. Although the park has a lot of diversity for its size, the main highlight is the Waterton lakes—the deepest in the Canadian Rockies—overlooked by the historic Prince of Wales Hotel.

Operated by Parks Canada, Waterton is open all year, but the main tourist season is during July and August. The only commercial facilities available within the park are located at the Waterton Park townsite. The park ranges in elevation from 1,290 metres (4,230ft) at the townsite to 2,920 m (9,580 ft) at Mount Blakiston. It offers many scenic trails, including Crypt Lake trail.

The park is part of the Waterton-Glacier International Peace Park, designated as World Heritage Site in 1995 for its scenery and wealth of plant and animal species. In 1979, Waterton was also designated a World Biosphere reserve, preserving mountains, highlands, lakes and freshwater wetlands ecosystems. Habitats represented in the park range include: prairie grasslands, aspen grove forests, alpine tundra/high meadows, arctic-alpine communities above the tree line, lower subalpine forests, deciduous and coniferous forests.