How to Tie: The Light Cahill

A world-renowned spring fly, this little dry is one of the best weapons an angler can have in their dry fly boxes when fishing for trout. In this week’s “How to Tie” video feature, Tim Flager from Tightline video returns to show us how to tie the Light Cahill.

Learn About This Fly

The light Cahill was invented by a new york railroad worker named Daniel Cahill back in the 1880s. Needless to say, this simple topwater fly quickly became an icon in the fly fishing community and has held true throughout over a century.

While this fly is known for its strength during the late spring and summer months, it can be effectively fished all the way through September in most areas in the US. This mayfly acts as a refreshing sight to many trout who have been feeding off underwater larvae for the majority of colder months, and who are now looking for a more protein-packed meal.

When tying this fly, a useful tip is to add a light finish of adhesive into the abdomen area in order to maintain the fly’s longevity. Often times, after long months of underwater feeding, trout can become very excited and slam topwater flies with an aggressive take. This fly is perfect for novice fly tiers who are looking to get into dry fly tying, as the ingredients and methods are rather simple, but will install crucial techniques for tying more complicated flies down the road.


  • TFS 100, sizes 14-18 hook 
  • Ultra 70 Tying Thread, cream
  • Super-Fine Dry Fly Dubbing, light Cahill
  • Lemon Wood Duck fibers
  • Dry Fly Hackle, light ginger (Hackle and tail)

Now you know how to tie the Light Cahill fly!

Video courtesy of Tightline video 

Ingredients courtesy of the fly shop

Article written by Fly Lords team member Wills Donaldson

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