Marshall Lake is a small marshy seasonal waterbody located about 9 miles southeast of Flagstaff on the Coconino National Forest, accessible via Lake Mary Road and Forest Road 128 (unpaved, may be impassable in wet conditions).

The site features a primitive boat launch on the east side, dispersed camping areas with pine-sheltered locations offering views of the San Francisco Peaks, and excellent wildlife viewing opportunities including waterfowl, elk, and wintering bald eagles.

Note that the northwest side is closed to vehicular traffic to protect nesting habitat, motorized boats are limited to 10 horsepower, and the area is typically open May through mid-October depending on weather conditions.