Waterton Lake (Paahtómahksikimi) is a mountain lake in southern Alberta, Canada, and northern Montana, United States. The lake is composed of two bodies of water, connected by a shallow channel known locally as the Bosporus. [1]

Upper Waterton Lake is the deepest lake in the Canadian Rockies and Alberta. Maximum depth is 487 ft. (148 m); length is 6.9 miles (11 km) by .5 mile (.8 km) at its widest.

While the town of Waterton Park is on Upper Waterton Lake, its most majestic parts can be seen in a variety of ways. The easiest would be walking some or all of the Lakeshore Trail.

Upper Waterton Lake lies in the south-central region of Waterton Park, 5 miles southwest of the park’s eastern entrance. Lake activities include boating, waterskiing, fishing, scuba-diving and nearby hiking trails, campgrounds and amenities.

Discover this 44.2-mile out-and-back trail near Polebridge, Montana. Generally considered a challenging route, it takes an average of 18 h 25 min to complete. This trail is great for backpacking, camping, and fishing, and it's unlikely you'll encounter many other people while exploring. The best times to visit this trail are June through October.

Upper Waterton Lake is a popular place with swimmers, as it is a bit warmer and perfectly clear waters. It’s also a great spot for those who would like to canoe or paddleboard.

The region’s base camp is the little town of Waterton nestled on the shores of Upper Waterton Lake. As its name implies, the area is best known for its vast lakes and water sports, but visitors will equally enjoy its breathtaking mountain scenery, scenic hiking trails, and rich biodiversity.

Upper Waterton Lake stretches for 7 miles from the Waterton Townsite, across the International Boundary, and ends in Glacier National Park’s Goat Haunt region. Middle Waterton Lake lies in the shadow of the Prince of Wales Hotel.

Visible from all over town, this is the deepest lake in the Canadian Rockies, sinking to a murky 120m. One of the best vantage points is from the Prince of Wales Hotel, where a classic view is framed by an ethereal collection of Gothic mountains, including Mt Cleveland, Glacier National Park’s highest peak.

Flanked by the breathtaking Canadian Rockies, the sparkling Upper and Middle Waterton Lakes are the largest bodies of water in the park. Upper Waterton Lake stretches 11 km (7 mi) from the Waterton townsite and is the deepest lake in the Canadian Rockies at 148m (487 ft).