Eastern Pacific: northern parts of Prince William Sound, Alaska, south to the Eel River in northern California, USA and is found in most streams emptying into the Pacific.
Widely introduced into various streams and lakes within its natural range, as well as into a few lakes in eastern North America. In some streams it may be the most numerous sport fish present, while other streams support only small populations. At least 14 subspecies have been historically recognized (Ref. 5723).