The Dead River is a 3.5 mile long (5.7 km) river located entirely in the city of Berlin in northern New Hampshire in the United States. It is a tributary of the Androscoggin River, which flows south and east into Maine, joining the Kennebec River near the Atlantic Ocean. The Dead River is formed where Jericho Brook, flowing out of the White Mountain National Forest and Jericho Lake State Park from the west, reaches a broad, flat valley occupied by NH Route 110 and the St. Lawrence and Atlantic Railroad. Flowing southeast through the valley, the river is nearly flat, or "dead", until it reaches the center of Berlin, where it drops 40 feet in one-half mile to reach the Androscoggin.