Greener and wetter than the St Mary Valley, the Lake McDonald Valley harbors the park’s largest lake and some of its densest and oldest temperate rainforest. Crisscrossed by a number of popular trails, including the wheelchair-accessible, 0.8-mile Trail of the Cedars, the area is popular with drive-in campers, who frequent the Sprague Creek and Avalanche Creek campgrounds, as well as winter cross-country skiers who use McDonald Creek and Going-to-the-Sun Rd as seasonal skiing trails.
The 2018 Howe Ridge fire, ignited by lightning, burned for more than a month in the area northwest of the lake and destroyed more than a dozen historic landholdings; the Upper McDonald Creek trail was still closed as of June 2019.
