About
Lowell Mills and the American Industrial Revolution. Through New Hampshire's Hillsborough and Merrimack counties, the Merrimack runs 117 miles of Class I-II water averaging 3,400 CFS — substantial volume that keeps it paddleable across a wide range of conditions. Optimal flows run from 1,000 to 6,000 CFS, with gauge 01092000 tracking the main stem. The upper stretch from Franklin to Concord holds the most consistent Class I-II features through the valley, while the Concord to Manchester section flattens to Class I as it passes the capital. Below Manchester to Nashua, the river picks up some Class II character again through the urban corridor. The Merrimack River Watershed Council coordinates both protection efforts and paddling access, and the river falls under New Hampshire's Rivers Management Program. At these flows, the Merrimack moves serious water — not technical, but with enough push to demand attention from recreational paddlers.
River conditions are community-verified. CFS ranges, difficulty ratings, and access points may not reflect every flow level or seasonal change. Always check current conditions, scout unfamiliar rapids, and paddle within your skill level.