The Little River is a 7.4 mile long (11.8 km) river in the White Mountains of New Hampshire in the United States. It is a tributary of the Ammonoosuc River and part of the Connecticut River watershed.
The Little River rises in the White Mountain National Forest in a small glacial cirque surrounded by Zealand Mountain to the east, Mount Guyot to the south, and South Twin Mountain to the west. The river flows north into the town of Bethlehem, through a deep valley between North Twin Mountain to the west and Mount Hale to the east. Eventually the river enters the town of Carroll near the community of Twin Mountain, passes under U.S. Route 3, and ends at the Ammonoosuc River.
The Little River is a public water supply for the village of Twin Mountain. A portion of the river is paralleled by (and crossed three times by) the North Twin Trail, a hiking trail.