The Rocky Branch is a 13.1-mile-long (21.1 km)[1] river in the White Mountains of New Hampshire in the United States.

It is a tributary of the Saco River, which flows to the Atlantic Ocean in Maine.

The Rocky Branch rises in the Presidential Range Dry River Wilderness Area of the White Mountain National Forest on the southernmost slopes of Mount Washington.

The river drops rapidly to the south through a valley between Montalban Ridge (with the peaks of Mount Isolation and Stairs Mountain) to the west and the lower Rocky Branch Ridge to the east.

The Rocky Branch Railroad supported a logging operation in the valley from 1908 to 1913.