It is located in the town of Newcomb in Essex County, flanked to the northeast by Cold Brook Pass and Iroquois Peak.

Originally named for Governor DeWitt Clinton, and then for mountain guide Herbert Clark, it was renamed for wilderness activist Bob Marshall after his death.

Mount Marshall is located within the High Peaks Wilderness Area of New York's Adirondack Park.

[1] Marshall is part of the MacIntyre Range, and is separated from Iroquois Peak to its northeast by a large valley known as Cold Brook Pass.

The first begins on the Cold Brook Pass near the key col between Marshall and Iroquois, and continues another 0.7 miles (1.1 km) uphill.

The second route involves hiking along Herbert Brook, starting at its intersection with the red-blazed trail 121 between the Calamity lean-tos and Lake Colden dam.