Steelhead are native to the West Coast of North America and to the Kamchatka Peninsula region of Russia. Steelhead were also planted in the Great lakes in the late 1800’s and early 1900’s, and now there are several steelhead runs in the Great Lakes watersheds. Even though the Great Lakes Steelhead Alley steelhead are the same species as the West Coast fish, the methods and flies for hunting them have evolved along their own lines. This evolution can be observed just by comparing the popular West Coast Steelhead fly patterns to the equally popular Great Lakes Steelhead Alley fly patterns. However, both groups of flies and the methods for fishing them will often work on either coast, so don't get stuck in a "regional rut" when you're on your favorite steelhead river.
Steelhead are anadromous (living in the sea and spawning in freshwater rivers) fish that were long considered to be sea-run Rainbow Trout. However, recent reclassification of the species has established the sea-run steelhead as the normal state for Rainbow Trout. Steelhead have been reclassified as members of the Pacific salmon family, and have been renamed Oncorhyncus mykiss (formerly Salmo gairdneri). Fortunately for fly anglers, the Steelhead don’t know that they’ve been reclassified, so they still take the same flies.