Merrimack River

The Merrimack River begins inNew Hampshire townFranklin, wherePemigewasset River (which starts inProfile Lake inFranconia mountains) joinsWinnipesaukee River (which flows outLake Winnipesaukee)formMerrimack.

Withtotal length110 miles,Merrimack has5,000-square-mile watershed that covers muchsouthern New Hampshire andportionnortheastern Massachusetts. On its banks arenumbersmall cities builttake advantagewater power in19th-century, when textile mills dominated New England economy: Concord (the state capital), Manchester,NashuaNew Hampshire,Lowell, Lawrence,HaverhillMassachusetts.

The riverbest known forearly American classicliterature, "A Week onConcordMerrimack River" by Henry David Thoreau.

Among its tributaries isSouhegan River, which extends west fromtownMerrimack.