Say which Penobscot you mean
When a Maine angler says the Penobscot, they almost always mean the West Branch below Ripogenus Dam, the Brookfield dam near Millinocket whose McKay Station powerhouse feeds the gorge and the ten-odd miles of river down to Abol Bridge and Ambajejus Lake. Paul McGurren, a Maine guide writing for the Georges River chapter of Trout Unlimited, calls it probably the finest landlocked salmon river fishery in the United States. Then there is the main stem, which begins at Medway where the West and East Branches meet and runs through West Enfield, Old Town and Bangor to the sea, smallmouth water for fifty miles with a returning run of sea-run fish. This page covers both, and it is honest about the gauge: USGS 01034500 at West Enfield is on the main stem below the Piscataquis and the Mattawamkeag, and it does not measure the West Branch. No USGS discharge gauge exists below Ripogenus; the number that matters there is Brookfield's.
Rip Dam to Abol Bridge
Below the dam the river drops through Ripogenus Gorge, vertical walls and whitewater, then settles into the water most anglers fish: the Golden Road runs along the south bank the whole way, so the known pools and runs, Big Eddy first among them, get pressure when the fishing is on. Matt LaRoche, who spent more than twenty years as park manager of the Penobscot River Corridor, names the section from Abol Bridge up to Ripogenus Dam as the best landlocked salmon fishing in Maine and singles out Nesowadnehunk Deadwater for evening rises. The Bureau of Parks and Lands keeps first-come campsites along the river, with private campgrounds at Big Eddy and Abol; wading works from the campgrounds, but the plunge pools and eddies fish best from a raft or drift boat. Everyone says the same thing about the fish: plenty of salmon, all selective, and the big ones are hard.
The brook trout are the other half. LaRoche says there are some very nice brookies in the West Branch, that they are less selective than the salmon, and that on a hot day a flying-ant fall will bring them up when the salmon ignore it.
Hendricksons on Memorial Day, then three weeks of caddis
LaRoche's two Northwoods Sporting Journal pieces set the West Branch calendar better than any chart. The Hendrickson is the first hatch, on or about Memorial Day weekend, late May into early June, and the salmon take a Comparadun drifted right and refuse almost everything else; when the risers turn to refusals just before dark, they have switched to spent spinners. The caddis start about the first week of June and run well into July, with mid-June hatches he describes as thick enough to breathe in. Fish jumping clear of the water are chasing pupae, not adults, and his answer is a size 14 or 16 pupa greased on the leader so it hangs just under the film; by late June the caddis are smaller and darker, size 18 black. Perfect Fly's sampling adds Blue-Winged Olives from April with a mid-May peak and a September return, Quill Gordons to mid-May, March Browns and Light Cahills in June, Little Yellow Stoneflies into July, a Hexagenia hatch from mid-June, and terrestrials from mid-July. Smelt streamers matter in spring and again for the fall salmon.
Reading Brookfield, not the USGS
Brookfield's Safe Waters page for McKay / Ripogenus posts the live total flow, a short-term schedule, and a hotline at 1-844-430-3569 for the stretches of the Golden Road with no signal. The license requires a minimum of 400 cfs below the dam, and during normal operation flows range from that minimum up to 3,200 cfs. The recreation releases that the rafting companies run on are scheduled from May 1 to September 15 between 8:30 a.m. and 5 p.m.: 2,300 cfs on Saturdays and Sundays, 2,200 on Mondays and Fridays and 2,000 Tuesday through Thursday in a normal year, 200 cfs lower across the board in a wet or dry year, with weekend releases only from September 16 to October 1. A Millinocket regular quoted by Colby's Fishing Professor blog put the ceiling plainly: over 3,000 cfs at McKay the bite is off. Mornings before 8:30 and evenings after 5 are the wading windows.
The station is not always predictable. On July 27, 2026 an unplanned turbine shutdown dropped the river from roughly 2,400 cfs to about 450 almost instantly and held it there for more than two hours, stranding juvenile salmon; a retired state biologist estimated 3,800 to 7,700 dead, the third such event in three years. Planned outages happen too: one began September 20, 2026 and was expected to run to about October 10, with nearly all flow routed through the upper gorge via the deep gates.
The main stem after the dams came out
Great Works Dam came out in 2012 and Veazie Dam in 2013, a bypass channel went in around Howland Dam on the Piscataquis in 2016, and Brookfield built a fish lift at Milford. Nearly 1.2 million river herring used that lift in 2017; by 2023 the count across the watershed was over six million. The river from Medway down to Old Town is smallmouth water, slower and best from a boat. Sea-run Atlantic salmon are federally endangered and there is no season on them anywhere in Maine.
This is the reach the West Enfield gauge measures. No shop publishes a wading number, so the 4,000 to 8,000 cfs range here is the gauge's own record: monthly medians since 1902 are about 28,900 cfs in April, 20,700 in May, 10,500 in June, 6,600 in July, 5,600 in August, 5,800 in September and 7,400 in October. Above 10,000 the main stem is a boat river; the summer trough is when the bass bars are wadeable.
Fly only to Telos Road, one salmon at 26 inches
The 2026 IFW lawbook splits the West Branch at its bridges. From Ripogenus Dam downstream to the Telos Road bridge it is fly fishing only from April 1 to September 30, with a one-salmon daily limit and a 26-inch minimum on landlocked salmon, which in practice makes the salmon water catch and release. From the Telos Road bridge to the red markers at the head of Pockwockamus Falls, April 1 to August 15 allows only artificial lures with one hook, single or treble, one salmon, 18-inch minimum; from August 16 to September 30 that reach goes to fly fishing only with a total limit of one trout or salmon and the same 18 inches. From Pockwockamus Falls down to Ambajejus Lake live baitfish are permitted. The general law 25-inch maximum on landlocked salmon does not apply on the West Branch.
On the main stem, Penobscot River, Medway to Veazie, is open to open water and ice fishing all year; from October 1 to December 31 it is artificial lures only and every trout, salmon and togue must be released. Everything within 150 feet of the Medway, West Enfield and Milford dams and their fishways is closed at all times. North of Route 11 and 157 the West Branch is North Zone water, with the general April 1 to August 15 river season and artificial lures only from August 16 to September 30.