Three sections of one river below the reservoir
NYSDEC splits the lower Neversink into three reaches, and the split is the best map you will get. Section 1 runs from the mouth of Wynkoop Brook, just below the Neversink Reservoir dam, downstream to a point one mile below Bridgeville Road near Monticello: a Stocked-Extended reach with both wild and hatchery browns, long smooth pools and short riffles, most of it reachable from the road. Section 2 begins at Mercer Brook and runs through the Neversink River Unique Area to the Sullivan and Orange county line: the gorge, not stocked, catch and release only. Section 3 picks up at the county line and runs down to the Guymard Turnpike crossing at Godeffroy, stocked again, with smallmouth bass mixed in as the river warms.
The dam that makes all this possible went into service in 1954 and drowned the water Theodore Gordon fished from Bradley and the Big Bend Club water Edward Hewitt bought in 1918. What it left behind is a bottom-release tailwater that stays cold through summer near the dam and warms steadily as it goes; DEC's own guidance is that by the time the water reaches the Unique Area in July it can be relatively warm.
Getting down into the gorge
There is no road to the river in the Unique Area. The most used trailhead is the Katrina Falls Road lot in Rock Hill, off exit 109 of Route 17, where the Blue Trail East drops toward the river with side trails to Mullet Brook Falls, Denton Falls and High Falls. Hiram Jones Road, Eden Road, Cold Spring Road and Hatchery Road have their own lots; Eden Road is a limited-maintenance road that DEC recommends for high-clearance vehicles, and the Hatchery Road trail descends more than 600 feet through the old Eden Brook hatchery to the site of a former suspension bridge. Round trips to fishable water run from under three miles to more than six, with 400 to 700 feet of elevation to climb back out.
Plan it like a hike, not a roadside stop. There is no cell service in the canyon, the property is open only from a half hour before sunrise to a half hour after sunset, and camping, fires and swimming are prohibited. Katrina Falls fills on weekends and holidays; DEC asks you to use one of the other lots rather than park on the road. Dark Skies Fly Fishing adds the two things the DEC page does not: black bears and timber rattlesnakes both live here, and a wading staff is not optional on the bedrock.
Wading the bedrock between Denton Falls and High Falls
Inside the gorge the river is thirty to sixty feet wide, bedrock and boulders more than cobble, with long deep pools and drop sequences below the falls and riffle-and-run water between them. It is slick, the current pushes hard when the flow is up, and Dark Skies' description of false steps being common is the honest one. Studded or felt boots, a belt and a staff, and a headlamp for the walk out. The fish are wild browns, with brook trout showing up now and then from tributaries like Mullet Brook, Wolf Brook and Eden Brook, and boulders and ledges hold them in predictable seams. Too much weight is the usual mistake; the rig hangs up instead of drifting.
Hatches Theodore Gordon would recognize
The Quill Gordon was tied for this river's early mayfly, and it still comes off here in April along with the Hendrickson, after the first Blue-Winged Olives of late March. Dark Skies' account of the season has March Browns and Gray Fox in May into June, Sulphurs through June in some sections, tan and cinnamon caddis in numbers through the warm months, and beetles, ants and inchworms out of the hemlocks all summer. Dette's late-summer reports note the upper Neversink turning on close to dark, like the East Branch. Quill Gordons emerge underwater at the streambed rather than at the surface, so a soft-hackle wet or an emerger often outfishes the dry, and cripple patterns beat perfect duns during the June Sulphurs. The Delaware River Club's Upper Delaware chart, which this river sits a county away from, puts the same insects within two weeks of these dates.
Reading the Bridgeville gauge before the hike
The Bridgeville gauge sits at the bottom of Section 1 and above the Unique Area, so it is the number for the gorge, and both DEC and Dark Skies point you to it. No shop publishes a wading range for the Neversink, so the range here comes from the USGS record: the monthly median at Bridgeville is about 350 cfs in April, 260 in May, 175 in June and 135 to 175 from July through October. Given how hard the bedrock fishes when the current is up, 100 to 300 cfs is the working window, and a spring reading near 350 means the gorge is a nymphing and streamer trip for experienced waders only. DEC's summer advice applies too: scan the previous day's hourly temperatures on the gauge, carry a thermometer, and stay off water over 70 degrees, which usually means fishing Section 1 closer to the dam or the cold tributaries.
Catch and release in the Unique Area, three fish above and below
The regulation table has three lines for the lower Neversink. The Unique Area reach, from the Sullivan and Orange county line upstream to Mercer Brook where the state owns the bank, is Catch and Release: open all year, no harvest, artificial lures only, and DEC's property rules repeat the artificial-lures restriction. Section 1, from one mile below Bridgeville Road upstream to Wynkoop Brook, and Section 3, from Guymard Turnpike upstream to the county line, are Stocked-Extended: April 1 through October 15, three trout a day with no more than one over 12 inches, then catch and release with artificials from October 16 to March 31. Bait is legal in those two reaches during the harvest season. The private frontage inside the Unique Area boundary where the fishing rights are not the state's is excluded from the no-kill and should be treated as posted.