Lake McDonald is the largest lake in Glacier National Park. It is located at 48°35′N 113°55′W in Flathead County in the U.S. state of Montana. Lake McDonald is approximately 10 miles (16 km) long, and over a mile (1.6 km) wide and 472 feet (130 m) deep, filling a valley formed by a combination of erosion and glacial activity.
The lake is home to numerous native species of trout, and other game fish. Catchable species include, but are not limited to – westslope cutthroat trout, rainbow trout, bull trout (char), lake trout (char), Lake Superior whitefish, mountain whitefish, kokanee salmon (landlocked sockeye), and suckers. However, the lake is nutrient-poor and is not considered a prime fishing destination. Grizzly bears, black bear, moose, and mule deer are found in many places near the lake but are most common on the north shore. The lake is surrounded by a dense coniferous forest dominated by various species of spruce, fir, and larch.