The Middle Branch of the Dead Diamond River is a 9.0 mile long (14.4 km) river

River

A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...

 in northern New Hampshire

New Hampshire

New Hampshire is a state in the New England region of the northeastern United States of America. The state was named after the southern English county of Hampshire. It is bordered by Massachusetts to the south, Vermont to the west, Maine and the Atlantic Ocean to the east, and the Canadian...

 in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

. It is a tributary of the East Branch

East Branch Dead Diamond River

The East Branch of the Dead Diamond River is a long 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....

 of the Dead Diamond River

Dead Diamond River

The Dead Diamond River is an 18.7 mile long river in northern New Hampshire in the United States. Its water enters the Atlantic Ocean on the coast of Maine by passing through the Magalloway, Androscoggin, and Kennebec rivers....

, located in the Androscoggin River

Androscoggin River

The Androscoggin River is a river in the U.S. states of Maine and New Hampshire, in northern New England. It is long and joins the Kennebec River at Merrymeeting Bay in Maine before its water empties into the Gulf of Maine on the Atlantic Ocean. Its drainage basin is in area...

 watershed

Drainage basin

A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...

 of Maine

Maine

Maine is a state in the New England region of the northeastern United States, bordered by the Atlantic Ocean to the east and south, New Hampshire to the west, and the Canadian provinces of Quebec to the northwest and New Brunswick to the northeast. Maine is both the northernmost and easternmost...

 and New Hampshire.

The Middle Branch flows for most of its length through Pittsburg

Pittsburg, New Hampshire

Pittsburg is a town in Coos County, New Hampshire, United States. The population was 869 at the 2010 census. It is the northernmost town in New Hampshire and the largest town by area in the state - and in New England as well - more than twice the size of the next largest town, Lincoln. U.S...

, the northernmost town in New Hampshire. It flows southeast through a wide valley between Magalloway Mountain (3,383 feet above sea level) to the south and Diamond Ridge (3,230 ft) to the north. The river then turns south and flows parallel to the East Branch of the Dead Diamond, finally joining it in the Atkinson and Gilmanton Grant

Atkinson and Gilmanton Academy Grant, New Hampshire

Atkinson and Gilmanton Academy Grant is a township in Coos County, New Hampshire, United States. It was granted by the state legislature to Gilmanton Academy and Atkinson Academy in equal shares in 1809 and contained about . It was later expanded by annexation of previously ungranted land to the...

, less than one mile upstream from the confluence of the East Branch and the West Branch

West Branch Dead Diamond River

The West Branch of the Dead Diamond River is a 2.7 mile long 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....

of the Dead Diamond.