Hatch profile
Ephemerella dorothea / invaria
Water-temperature trigger
Top fly patterns
The most important mayfly hatch on Eastern rivers. Reliable emergence + spinner fall every evening for 4-6 weeks. Match the spinners with rusty-bodied patterns.
Best rivers
Pennsylvania
Penns Creek
May 20 – Jun 25 · heavy
Pennsylvania
Spring Creek
May 20 – Jun 25 · heavy
Pennsylvania
Brodhead Creek
May 25 – Jun 25 · heavy
Pennsylvania
Letort Spring Run
May 20 – Jun 25 · heavy
Pennsylvania
Yellow Breeches Creek
May 20 – Jun 25 · heavy
Pennsylvania
Big Fishing Creek
May 25 – Jun 25 · heavy
Pennsylvania
Loyalsock Creek
May 25 – Jun 25 · heavy
Pennsylvania
Falling Springs Branch
May 20 – Jun 25 · heavy
Pennsylvania
Little Juniata River
May 20 – Jun 25 · heavy
Pennsylvania
Upper Delaware River
May 25 – Jul 5 · heavy
New York
West Branch Delaware River
May 25 – Jul 5 · heavy
New York
Beaverkill River
Jun 1 – Jun 30 · heavy
New York
Esopus Creek
Jun 1 – Jun 30 · heavy
Virginia
New River
May 5 – Jun 1 · heavy
Virginia
Mossy Creek
May 20 – Jun 25 · heavy
Virginia
Rose River
May 20 – Jun 25 · heavy
Virginia
Roaring Run
May 20 – Jun 25 · heavy
Virginia
Jackson River
May 25 – Jul 5 · heavy
West Virginia
Cranberry River
May 20 – Jun 25 · heavy
West Virginia
Elk River (headwaters)
May 20 – Jun 25 · heavy
West Virginia
Shavers Fork
May 20 – Jun 25 · heavy
West Virginia
North Fork South Branch Potomac
May 25 – Jun 25 · heavy
North Carolina
Davidson River
May 20 – Jun 25 · heavy
North Carolina
South Toe River
May 20 – Jun 25 · heavy
North Carolina
Nantahala River
May 25 – Jul 5 · heavy
North Carolina
Chattooga River (upper)
May 20 – Jun 25 · heavy
North Carolina
Watauga River (NC)
May 25 – Jul 5 · heavy
Tennessee
South Holston River
May 15 – Aug 15 · heavy
Tennessee
Watauga River (TN)
May 25 – Jul 5 · heavy
Tennessee
Clinch River
May 1 – Jun 15 · heavy
Tennessee
Caney Fork River
May 25 – Jul 5 · heavy
Georgia
Chattahoochee River (upper)
May 25 – Jul 5 · heavy
Georgia
Toccoa River
May 25 – Jul 5 · heavy
Georgia
Conasauga River
May 20 – Jun 25 · heavy
Maryland
Gunpowder Falls
May 25 – Jul 5 · heavy
Maryland
Big Gunpowder Falls (freestone upper)
May 25 – Jun 25 · heavy
Maryland
North Branch Potomac River
May 25 – Jul 5 · heavy
New Jersey
South Branch Raritan River
May 20 – Jun 25 · heavy
New Jersey
Musconetcong River
May 25 – Jun 25 · heavy
Connecticut
Farmington River
May 25 – Jul 5 · heavy
Connecticut
Housatonic River
Jun 1 – Jul 5 · heavy
Vermont
Battenkill River
Jun 1 – Jul 5 · heavy
Vermont
Lamoille River
Jun 10 – Jul 10 · heavy
New Hampshire
Upper Connecticut River
Jun 10 – Jul 10 · heavy
Maine
Kennebago River
Jun 10 – Jul 10 · heavy
Maine
Rapid River
Jun 10 – Jul 10 · heavy
Other rivers with Sulphur activity
Bield Fish watches USGS water-temp gauges for your home water and pings you when conditions hit the 55–68°F trigger window.
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