The East Branch of the Pemigewasset River is a 15.8-mile-long (25.4 km) river located in the White Mountains of New Hampshire in the United States. It is a tributary of the Pemigewasset River, part of the Merrimack River watershed.
The East Branch is a longer and larger river than the river that it flows into, but it is named a branch of the main stem because its source lies deep in the Pemigewasset Wilderness of the White Mountains, while the main Pemigewasset River flows directly from Franconia Notch, a major pass through the mountains. The East Branch begins in the locality known as Stillwater, in a wide valley north of Mount Carrigain and Mount Hancock, where several large brooks converge.