Errol Dam to the Bragg Bay markers
The Androscoggin begins in Errol where the Magalloway meets the outlet of Lake Umbagog, and the Errol Dam controls what comes out. From that dam down to the markers at the dead water at Bragg Bay the river is fly fishing only, two trout a day with a 12-inch minimum, under the 2026 NH Fish and Game digest. Every guide service that works the river points here first: New Hampshire Rivers Guide Service calls the fly-only water below the dam the best wading on the river and the most reliable place to find a landlocked salmon, and Top Notch Fly Fishing describes Umbagog's shallow, warm, fertile water as the reason the insects are oversized and the fish grow fast. The Seven Islands Bridge in Errol is one of the access points Perfect Fly lists below town. L.L. Cote and Percy's Flies, both in Errol, are the shops.
Route 16 through the Thirteen Mile Woods
Route 16 runs beside the river for more than twenty miles below Errol, and the pull-offs are the access: the Androscoggin Wayside in the Thirteen Mile Woods scenic area, Mollidgewock State Park's riverside campground, the Dummer access, and then the Pontook Dam. Perfect Fly describes the reach as a mix of fast rapids, long riffles and slower water, best covered by canoe or raft, and it is the water Orvis's North Country Angler report recommends fishing from Errol to Pontook. Below Pontook the river is flat before it drops toward Berlin. The digest splits this water into pieces with their own rules: from the Dummer and Cambridge town line to Pontook Dam there is no closed season and two trout may be kept through the ice, and from Wheeler Bay in Dummer down to the Sawmill Dam in Berlin brown trout may be fished for at any hour of the day or night.
Alder flies from mid June, Isonychia in September
New Hampshire Rivers Guide Service says the most popular time to fish the river is the alder fly hatch, which usually falls somewhere between mid June and early July. Perfect Fly calls the same insect the Zebra Caddis, a big bug that brings big fish up, and puts a large olive-bodied mayfly it calls the Great Winged Olive Dun in late June into early July alongside it. FlyFishFinder's Androscoggin chart adds March Browns overlapping Hendricksons in late May, Green Drakes in late June on the Errol-area pools, Isonychia in September that fish take on the swing as readily as on top, and Blue-Winged Olives in April and October. North Country Angler's Orvis report lists midges, black stones and caddis as the standbys and says dry flies at dusk produced the larger fish in late July 2026. Outside the alder fly window the same report's advice is streamers and nymphs on the upper river, and it notes the lower river from Berlin to Maine rises fish to dries almost year round.
What 1,000 cfs looks like at Errol
This is big water. Orvis's description gives an average of about 1,200 cfs in the upper river and 2,000 lower down, and the USGS record at Errol has typical monthly flows of roughly 1,800 to 2,100 cfs from January through April, 2,800 in May, 2,000 in June, 1,700 in July and August, and 1,500 to 1,700 in September and October, so the river only settles into wading shape when Umbagog's release comes down in summer and fall. RiverReports' New Hampshire brief treats 1,500 cfs as the wading threshold and called 1,180 to 1,310 cfs in August 2026 accessible through the Errol to Pontook section; this page compares the live Errol reading to 500 to 1,500 cfs on that basis, and anything above it is float water, which Top Notch, Orvis and Perfect Fly all say is the better way to fish the river anyway. Summer temperatures run mid 60s; Orvis's late July report read 65 degrees, and Top Notch says the river warms enough that May, June, September and October are the months.
Berlin to the Maine line: the catch-and-release river
Below the Sawmill Dam in Berlin the rules flip: no closed season, single barbless hooks, artificial lures and flies only, and catch and release for every species down to the state line. Top Notch describes this lower river through Gorham and Shelburne as long shallow riffles between a series of dams, wadeable in Gorham and a float below the Shelburne Dam, with wild rainbows of 8 to 14 inches now the dominant fish where big browns once were, and no stocking by the state. RiverReports dates the river's recovery to the paper mill closing in 2006 and calls this the largest stretch of catch-and-release water in New England. The Gorham gauge, USGS 01054000, is the reference for this reach.
Seasons and limits, Errol to Shelburne
General river rules in New Hampshire give trout a January 1 to October 15 season with a five-fish or five-pound limit and no length limit, close most rivers entirely from October 16 through December 31, and prohibit ice fishing unless a water is listed. On the Androscoggin the listed exceptions are the ones above: fly only and two trout of 12 inches from Errol Dam to Bragg Bay; no closed season and two trout through the ice from the Dummer and Cambridge line to Pontook Dam; night fishing for browns from Wheeler Bay to the Sawmill Dam; and no closed season, barbless artificials and full catch and release from the Sawmill Dam to Maine. Landlocked salmon are open April 1 to September 30 everywhere, two fish, 15-inch minimum, and may not be taken through the ice. Smallmouth follow the statewide bass calendar, catch and release from May 15 to June 15.