An investigation of the genetic and meristic patterns of coastal cutthroat trout (Oncorhynchus clarki clarki) in two coastal basins, one in Oregon and one in Alaska, revealed varying degrees of differences among populations within each site. Coastal cutthroat trout collected from seven sites above and below barriers from Elk River, Oregon were characterized by significant genetic structuring (Fst=0.095) based on allozymes and significant differences among nine meristic characters. This may reflect the geologic history and local conditions of the Elk River Basin. Despite this divergence, Elk River populations were relatively similar to each other (Nei's genetic identity> 0.0987), suggesting that these populations share common ancestry. Fewer differences were detected among the coastal cutthroat trout from four sites below and above a barrier within Vixen Inlet, Alaska. Genetic structuring among populations was low (Fst=0.016) and significant differences were detected in only two of nine meristic characters. This may reflect the recent glacial history of southeast Alaska. In both sites, there was concordance between allozyme data and meristic data. / Graduation date: 1996