Lake McDonald, Glacial lake in Glacier National Park, Montana, US

Lake McDonald is the largest lake in Glacier National Park, about 10 miles (16 km) long, over a mile (1.6 km) wide and 472 feet (130 m) deep, with a surface area of 6,823 acres (27.6 km2). It fills a valley shaped by erosion and glacial activity at 3,153 feet (961 m) on the west side of the Continental Divide. Going-to-the-Sun Road runs along its southern shore, and a dense coniferous forest of spruce, fir and larch surrounds the water.

The lake fills a valley shaped by erosion and glacial activity, lying at 3,153 feet on the west side of the Continental Divide. In 1878 Duncan McDonald, a Hudson's Bay Company trader working the Flathead Valley, carved his name on a tree near the shore, and the lake took his name. Lake McDonald Lodge was built in 1913–14 to resemble a rustic hunting lodge with Swiss-influenced architecture.

The Kootenai called the lake by Ya Kit Haqwitnamki, "The Place Where They Dance", after their campsite at Apgar where they met for ceremonies. The lake itself is named for Duncan McDonald, a Hudson's Bay Company trader who carved his name on a tree near the shore in 1878.

Four campgrounds sit near the lake (Apgar, Avalanche, Fish Creek, and Sprague Creek), each offering basic facilities for overnight camping. The best visiting window is late spring through early fall when the access roads are open and weather is mild.

The lake's Kootenai name, Ya Kit Haqwitnamki ("The Place Where They Dance"), referred to the campsite at Apgar, where ceremonies were held. Duncan McDonald, a Hudson's Bay Company trader, carved his name on a tree near the lake in 1878, giving the lake its present name.