Merrimack River
Hillsborough / Merrimack Co. · 117 mi · Class I–II
8,350CFS/ 6.09 ft
Above Optimal↓Falling slowly (-40 cfs/hr)· -80 cfs in 3h
Optimal: 1000–6000 CFS · USGS #01092000
Length
Difficulty
Optimal
Avg Flow
Hist. Median
USGS Gauge
Merrimack River Watershed Council · New Hampshire Rivers Management Program
New Hampshire's great central river flows 117 miles from Franklin through Concord and Manchester to the Massachusetts border. The Merrimack powered America's textile revolution and has since recovered into one of southern New Hampshire's best paddling corridors — Class I–II water through the state capital and the largest city in northern New England.
Trip sections
Franklin to Concord — Class I–II, upper valley
Concord to Manchester — Class I, capital city run
Manchester to Nashua — Class I–II, urban corridor
Outfitters
Merrimack River Watershed Council
Guided paddles and access information, Concord NH
72-Hour Flow Forecast
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10-Year Flow Patterns
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Data Quality
River conditions are community-verified. CFS ranges, difficulty ratings, and trip sections may not reflect every flow level or seasonal change. Always check current conditions, scout unfamiliar rapids, and paddle within your skill level. If you spot an error, use the Improve This River button at the top of the page — your local knowledge is what makes this atlas accurate.