In northern California, several watersheds contain populations of reputed redband trout (Oncorhynchus mykiss subspp.), including drainages of the Pit River, Goose Lake, Warner Valley, and McCloud River. Redband trout in the upper McCloud River watershed, O. m. subsp., is an apparently unique subspecies of redband trout native to Shasta County, California. Presently, the upper McCloud River redband trout are believed to be restricted to several small streams in the upper McCloud River basin and the McCloud River main stem above Middle Falls, located about 10 miles east of the town of McCloud. The relationship between these populations, as well as redbands of Goose Lake and the Upper Pit River watershed (O. m. newberrii), is not understood, thus there is uncertainty regarding their status as distinct taxonomic units. Using a library of SNPs developed against hatchery rainbow trout and putative pure redband trout populations, I am attempting to determine the extent of hatchery rainbow-upper McCloud redband trout hybridization in more degraded streams, assess population structure within the McCloud River drainage, and refine the genetic relationships of upper McCloud River redband trout and other redband populations. This study will provide insights on management and recovery of upper McCloud River redband trout, other redband trout, and possibly other native resident trout populations throughout the western US.