The Little Sugar River is a 13.5 miles (21.7 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...

 located in western 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

Tributary

A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

 of the Connecticut River

Connecticut River

The Connecticut River is the largest and longest river in New England, and also an American Heritage River. It flows roughly south, starting from the Fourth Connecticut Lake in New Hampshire. After flowing through the remaining Connecticut Lakes and Lake Francis, it defines the border between the...

, which flows to Long Island Sound

Long Island Sound

Long Island Sound is an estuary of the Atlantic Ocean, located in the United States between Connecticut to the north and Long Island, New York to the south. The mouth of the Connecticut River at Old Saybrook, Connecticut, empties into the sound. On its western end the sound is bounded by the Bronx...

. The river flows parallel to and approximately 5 miles (8 km) south of the Sugar River

Sugar River (New Hampshire)

The Sugar River is a 27.0 mile long river located in western New Hampshire in the United States. It is a tributary of the Connecticut River, which flows to Long Island Sound....

.

The Little Sugar River begins on a tableland

Plateau

In geology and earth science, a plateau , also called a high plain or tableland, is an area of highland, usually consisting of relatively flat terrain. A highly eroded plateau is called a dissected plateau...

 in the town of Unity, New Hampshire

Unity, New Hampshire

Unity is a town in Sullivan County, New Hampshire, United States. The population was 1,671 at the 2010 census. The town includes the villages of Unity, East Unity, Quaker City, and West Unity.- Geography :...

, then drops rapidly to the west, cutting a small gorge

Canyon

A canyon or gorge is a deep ravine between cliffs often carved from the landscape by a river. Rivers have a natural tendency to reach a baseline elevation, which is the same elevation as the body of water it will eventually drain into. This forms a canyon. Most canyons were formed by a process of...

 past the north end of Perry Mountain, and enters the town of Charlestown

Charlestown, New Hampshire

Charlestown is a town in Sullivan County, New Hampshire, United States. The population was 5,114 at the 2010 census. The town is home to Hubbard State Forest and the headquarters of the Student Conservation Association....

. The river reaches the Connecticut just west of the village of North Charlestown.