The Cochecho River or Cocheco River is a tributary of the Piscataqua River

Piscataqua River

The Piscataqua River, in the northeastern United States, is a long tidal estuary formed by the confluence of the Salmon Falls and Cocheco rivers...

, 38.3 miles (61.6 km) long, in the U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of 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...

. It rises in northern Strafford County and runs southeastward, through the town of Farmington

Farmington, New Hampshire

Farmington is a town located in Strafford County, New Hampshire, USA. The 2010 census reported that the town had a total population of 6,786. Farmington is home to Blue Job State Forest....

 and the cities of Rochester

Rochester, New Hampshire

Rochester is a city in Strafford County, New Hampshire, United States. As of the 2010 census, the city population was 29,752. The city includes the villages of East Rochester and Gonic. Rochester is home to Skyhaven Airport and the annual Rochester Fair....

 and Dover

Dover, New Hampshire

Dover is a city in Strafford County, New Hampshire, in the United States of America. The population was 29,987 at the 2010 census, the largest in the New Hampshire Seacoast region...

, where it provides hydroelectric power. Below the center of Dover, the river is tidal

Tidal river

A tidal river is a river, or more typically a stretch of a river, whose flow and level is influenced by tides. An example of a tidal river is the portion of the Connecticut River flowing from Windsor Locks, Connecticut, to the Atlantic Ocean. The Brisbane River, which flows into the Pacific Ocean...

 and joins the Salmon Falls River

Salmon Falls River

The Salmon Falls River is a tributary of the Piscataqua River in the U.S. states of Maine and New Hampshire. It rises at Great East Lake and flows south-southeast for approximately , forming the border between Maine and New Hampshire....

 at the 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...

 border to form the Piscataqua.

Cochecho is an Abenaki word believed to mean "rapid foaming water", referring to the river's falls in today's downtown Dover. Settlers adopted the name for the entire river. It is believed that the shift from Cochecho to Cocheco can be traced to a clerical error at the 1827 incorporation of the defunct Cocheco Manufacturing Company. The spelling "Cocheco" was adopted as the official name of the river in a 1911 decision by the United States Board on Geographic Names

United States Board on Geographic Names

The United States Board on Geographic Names is a United States federal body whose purpose is to establish and maintain uniform usage of geographic names throughout the U.S. government.-Overview:...

. The river has also been known as the Dover River.

Significant tributaries include the Ela River

Ela River

The Ela River is a 10.6 mile long river located in eastern New Hampshire in the United States. It is a tributary of the Cocheco River, part of the Piscataqua River watershed leading to the Atlantic Ocean....

, the Mad River

Mad River (Cocheco River)

The Mad River is a 5.2 mile long river in eastern New Hampshire in the United States. It is a tributary of the Cocheco River, part of the Piscataqua River watershed leading to the Atlantic Ocean....

, and the Isinglass River

Isinglass River

The Isinglass River in Strafford County, southeastern New Hampshire, the United States, is about 15 miles long. It rises at Bow Lake in Strafford, but is also fed through its tributaries by Ayer's, Nippo, Round and Long Ponds in Barrington. The Isinglass flows east to meet the Cochecho River below...

.