This is a very popular pattern in the US and works well on both the east and west side of the country. It was designed by Leonard Halladay from Michigan in 1922 at the request of one of his friends
Adams is one of those patterns that imitates nothing in particular but is similar to most of the insects the trout feeds on. Depending on the size it’s tied in it can imitate thing like the callibaetis du, blue winged olives and even green drakes and much more. If it turns out that the fish is only feeding on the crippled emerging mayflies, try to trim the hackle and present it in the surface film.
Halladay moved to Michigan as a young boy pursuing jobs in the lumber industry which at the time was big in the area and being used to fishing for brook trout and grayling he faced a new challenge as Michigan had introduced the German brown trout into the rivers. At a very young age, he did not only enjoy hunting and breeding dogs but he was also an acknowledged fly fisher and fly tier that even raised his own chickens for hackle feathers.
As the lumbering industry decreased in size the fishing in the area increased and Halladay spent more and more guiding fisherman from distant places. One of those was a man named Charles F. Adams. This was the man who would later fish the pattern for the very first time at the pond outside Halladay's house and get the pattern named after him. Let’s face it, the Adams fly really works well. Arguably the most productive dry-fly ever produced and cast over rising trout for the past 90 years.
If you want to learn how to tie the Adams, Check out our pattern database