The Merrimack River (or Merrimac River, an occasional earlier spelling ) is a 117-mile-long (188 km) river in the northeastern United States. It rises at the confluence of the Pemigewasset and Winnipesaukee See more

History of pollution
Since 1951, the Merrimack River has seen many alterations and pollutants. It was dammed and canalled, as well as used as a dumping spot for See more

While the Merrimack River is prone to minor flooding, on May 15, 2006, rainfall raised the river more than 8 feet (2.4 m) above flood stage, forcing evacuations, damaging property, and breaking the main sewage pipeline in the city of Haverhill, Massachusetts See more

The etymology of the name of the Merrimack River—from which all subsequent uses derive, such as the name of the Civil War ironclad—remains uncertain. See more

Prior to glaciation, the Merrimack continued its southward course far beyond the present day New Hampshire-Massachusetts border to enter the Gulf of Maine near See more

The Merrimack is listed as one of the Navigable Waters of the United States, subject to Section 10, Rivers and Harbors Act Jurisdiction. See more

The most significant flood in the recorded history of the Merrimack was in March 1936, when a double flood of rain and melting snow and ice … See more