The East Branch of the Dead Diamond River is a 12.7 mi river in northern New Hampshire in the United States. It is a tributary of the Dead Diamond River, located in the Androscoggin River watershed of Maine and New Hampshire. The East Branch of the Dead Diamond River rises in the town of Pittsburg between 3627 ft Stub Hill and 3230 ft Diamond Ridge. Nearly the entire length of the river is in Pittsburg, with a small portion at its southern end in the Atkinson and Gilmanton Academy Grant. A highlight along the river are the 40 ft Garfield Falls.