Hillsborough to West Henniker: where the cold water is
The Contoocook is a 71-mile river that runs the wrong way for New Hampshire, north from Rindge to the Merrimack at Concord, and it drops more than 700 feet on the way. The New Hampshire Department of Environmental Services, quoted by the Five Rivers Conservation Trust, says the most significant high-quality coldwater habitat on the whole river is the run of rapids between Hillsborough and West Henniker, the same water that holds the Class III and IV Freight Train rapids paddlers come for. Routes 202 and 9 follow it, and the pull-offs between the two towns are the access. Tim Huckaby's account of a June morning here, fished on a tip from the state Trout Unlimited president, is the honest picture: a first pull-off with pocket water behind a swamp, a second a half mile down with 200 yards of pockets, riffles, runs and tailouts, tannic water with no visibility in the shade, and brook, brown and rainbow trout plus a smallmouth in ninety minutes with big caddis and yellow sallies in the air. Morse Sporting Goods in Hillsborough sells licenses and local flies.
The Henniker special section, marked by signs and wire
One mile of the river carries its own rules. From a point 2,500 feet above the former paper mill dam in West Henniker, upstream one mile to a point marked by signs and wire, the 2026 digest sets a January 1 through November 30 season, single-hook artificial lures and flies only, and a two-trout limit with a 12-inch minimum. That is the only Contoocook water with a length limit and the only water that stays open through November. Henniker village and New England College are just downstream, with a riverfront park in town, and the state stocks rainbows, browns and brook trout each spring on top of the native brook trout the regional guides say are still in the system.
Below Henniker: the flood-control pool and the smallmouth river
The character changes below Henniker. From 2,500 feet above the West Henniker dam down to the confluence with the Merrimack there is no closed season and two trout may be kept through the ice; the reach includes the Hopkinton-Everett flood control area behind the Hopkinton Dam, where a second USGS gauge, 01085500 below the dam at West Hopkinton, reads the outflow. Five Rivers describes the lower river from Contoocook village to the island at Penacook as flatwater with motorboats, and New Hampshire Rivers Guide Service says smallmouth bass are the fish from the lake to the Merrimack, with trout only near cold tributary mouths. New Hampshire Rivers Guide Service's window for the southern rivers is mid to late April into mid to late June for trout, with the bass fishing taking over later.
Upstream: Peterborough, Contoocook Lake and the Rindge headwaters
Above Hillsborough the river is smaller and wilder. From Contoocook Lake in Rindge downstream to the signs and wire in West Henniker the digest lists no closed season and a two-trout limit through the ice, and FlyFishFinder puts wild brook trout in the Peterborough reaches with wild browns mixed among the stocked fish in the middle river. The Peterborough gauge, USGS 01082000, drains a fraction of what Henniker sees, which is why a reading of 20 cfs there in September is a normal number and not a drought. Sand Brook in Hillsborough, a tributary, is one of the state's managed wild trout streams: January 1 to Labor Day, catch and release, single barbless hooks, artificials only.
Reading the Henniker gauge
No shop publishes a wading number for the Contoocook, so this page uses the USGS record at Henniker, USGS 01085000 just above the Hopkinton pool, and says so. Typical monthly flows there run about 1,700 cfs in April, 900 in May, 400 in June, 175 in July, 150 in August and September, 190 in October and 430 in November. The Hillsborough to Henniker rapids are pocket water that wades comfortably at the summer and early fall base flows and turns into a whitewater run in spring, so the page compares the live reading to 150 to 500 cfs: the June median at the top, the late-summer base at the bottom. Below about 150 the river is low and clear and the fish are in the deeper pockets; above 500 the rapids are for boats.
What comes off, from a regional chart
There is no Contoocook-specific hatch chart from a local shop, so the calendar here is FlyFishFinder's for the river cross-checked against Huckaby's June observations and the statewide pattern. FlyFishFinder gives Hendricksons in early to mid May on overcast afternoons in the 50s, evening Sulphurs late June through July on the flatter water, Isonychia in September that bring the bigger browns back into view, and Blue-Winged Olives in April and October, with Tricos on slower stretches in summer. The big caddis and yellow sallies Huckaby watched in mid June fill the gap between. Treat the dates as a starting point rather than a promise; the rows are marked unverifiable for that reason.