The West Branch of the Peabody is within the Great Gulf Wilderness of the White Mountain National Forest for most of its length.

It is paralleled by the Great Gulf Trail, a popular route for backpackers.

The stream rises in Great Gulf, a large glacial cirque on the northern side of Mount Washington.

The West Branch flows from the outlet of Spaulding Lake, a tarn seated at the foot of the east face of Mount Clay, and proceeds northeast deeper into the gulf, with Mount Jefferson of the Presidential Range to the west and Chandlers Ridge, a northern spur of Mount Washington, to the east.

The river ends at the Peabody River, 1.5 miles (2.4 km) north (downstream) of Glen House, the entrance to the Mount Washington Auto Road.