Every spring for a few weeks in late May and early June, something happens on Penns Creek in central Pennsylvania that draws fly fishers from across the country. The Green Drake — Ephemera guttulata, the largest and most important mayfly hatch in the eastern United States — emerges from the limestone substrate in numbers dense enough to blacken the water surface. It's the event that defines Penns Creek and the reason this river punches above its weight on a national scale.
The Insect: Ephemera guttulata
The Green Drake is a large burrowing mayfly in the family Ephemeridae — the same family as Michigan's Hexagenia limbata, though it's smaller (size #8 to #10) and a daytime/evening emerger rather than a purely nocturnal one. The nymphs spend two years in the silt and sand of limestone stream bottoms before emerging as adults.
The dun is distinctive and hard to miss: a pale cream-to-olive body with large upright wings that are distinctly mottled or stippled in gray and cream. These are not subtle insects. A good emergence covers the water so thoroughly that the surface loses its texture under the mat of wings.
The two stages that matter: The dun (newly emerged adult) rides the surface after emergence, vulnerable and highly visible — fish during the emergence itself. The spinner (the sexually mature adult that returns to the water to lay eggs and die) falls spent on the surface, often in more concentrated numbers than the emergence — fish the spinner fall at dusk and into dark. Carry both imitations.
Timing: When the Hatch Happens
The Green Drake emergence on Penns Creek typically runs from Memorial Day weekend through mid-June, with the peak usually in the first two weeks of June. Water temperature drives the schedule — the hatch begins in earnest when afternoon water temps approach 58–62°F and tends to slow as summer warms the water above 65°F.
The emergence itself is an afternoon and evening event. Unlike morning hatches such as the Trico or Sulphur spinner fall, Green Drakes come off in force from roughly 4 PM through dusk, with spinner falls following as light fades. This timing means anglers are on the water during the best light of the day — and are sharing it with a lot of other people who know the same thing.
Scouting before the hatch starts pays off. Arrive early afternoon, walk the water you plan to fish, identify the holding lies (deep runs below riffles, banks with undercut structure, the inside of bends where current slows). When the hatch begins you won't be moving around — you'll be locked onto rising fish in a specific position.
Penns Creek: The River
Penns Creek is a limestone spring creek in Centre County, flowing east through Brush Valley and the Seven Mountains region before joining the Susquehanna River at Penns Creek village. The main trout water runs through public access on the Poe Paddy / Bald Eagle State Forest sections, with multiple public access points documented on the Pennsylvania Fish and Boat Commission (PFBC) website.
The character of the water matters for understanding the hatch. Penns Creek is a limestone stream — groundwater-fed, cold and clear, with a rich macroinvertebrate community in the silt-and-gravel substrate that burrowing mayflies depend on. The water maintains consistent temperatures (typically 54–60°F through summer) that allow for a longer hatch window than warmer freestone streams.
The main trout section from Coburn downstream to Cherry Run has the highest density of Green Drake water and the most fishing pressure during hatch season. The river widens in this reach and allows wade fishing throughout; the gradient is gentle, and the surface smooth enough to make rising fish visible at distance.
Crowds are real during peak hatch week. Penns Creek during the Green Drake draws anglers from across the region. The most productive approach is to fish access points that require a longer walk from the road, arrive before the hatch to secure your position, and practice ethical stream etiquette — don't crowd another angler who is already set up on rising fish.
Flies and Tactics
Matching the dun
the core presentation
A parachute Green Drake in size #10 or #12 is the standard imitation for the dun phase. Parachutes sit flush in the film, are visible to the angler even in low light, and present a realistic silhouette. Extended-body patterns and traditional Catskill-tied Green Drakes also work, particularly on flat water where fish have time to inspect.
Penns Creek trout during heavy emergence are not necessarily picky — there are so many naturals on the water that you can pick your rising fish and trust the pattern. What matters more than exact pattern is drag-free drift. Penns Creek has subtle cross-currents and current lanes that will drag your fly off a trout's feeding lane in seconds if you don't mend correctly.
The spinner fall
often overlooked, frequently better
The Green Drake spinner (sometimes called the Coffin Fly, for its pale cream-and-white spent body) falls on the water as light fades to dusk. Spinner falls are lower-visibility presentations for the angler — you are fishing to sound and to the silhouettes of rising fish against the last light — but the feeding is often more concentrated and committed than during the emergence.
Fish a spent-wing imitation in cream or pale yellow, size #10–#12. Trim the hackle flush under the body or use CDC wings to keep the fly flat in the surface film. Listen for rises as much as look for them after dusk.
Nymphing before the hatch
burrowing nymph imitations, size #8–#10
In the two to three hours before the surface emergence, large burrowing mayfly nymphs become active in the water column and fish feed on them below the surface. A weighted Hexagenia-style burrowing nymph — pale cream/tan, size #8 or #10, fished deep with a tight-line or strike indicator rig — can be extremely productive in the pre-hatch window. When you start seeing adult wings in the air and occasional sipping rises, switch to a dry fly.
The Rest of the Hatch Season
The Green Drake doesn't arrive alone. The weeks surrounding the Green Drake emergence are the richest of the Pennsylvania fishing year:
March Brown and Gray Fox (Maccaffertium vicarium) overlap with the early Green Drake emergence in late May. These size #10–#12 duns come off in afternoon emergences and are often the first significant hatch of the day before the Green Drakes appear.
Sulphurs (Ephemerella dorothea) overlap and follow the Green Drake, running through June and into July on Pennsylvania limestone creeks. Sulphurs are smaller (size #14–#16) and more technical; the evening spinner falls can be some of the most challenging dry fly fishing on the East Coast.
Light Cahill and Cahills continue through the summer on Penns Creek and its limestone tributaries, providing consistent evening hatches well into August.
Multi-hatch strategy: A week on Penns Creek in early June typically gives you March Browns in the afternoon, Green Drakes at the evening emergence, and Green Drake spinners at dusk — followed by Sulphur hatches from the second week onward. You don't need to be there on the single best day. A few-day trip covers multiple hatches and stages.
Access and Regulations
Penns Creek trout water is managed under Pennsylvania's Special Regulations framework on several reaches. The section through the Poe Paddy State Park area includes an artificial-lures-only, catch-and-release section — check PFBC boundary markers before fishing, as regulations vary by reach. The main trout season runs from the opening day (first Saturday after April 11) through Labor Day in most sections.
Public access is well-documented via the PFBC's Fishing Access information and the Bald Eagle State Forest trail maps. The Penns Creek Rail Trail follows the river through several key miles of trout water, providing walk-in access to water that's away from road-accessible parking areas. See the Pennsylvania regulations guide for current license requirements and season dates.