For several species of Pacific salmon (Oncorhynchus spp.) inhabiting coastal temperate streams, juvenile fish have been recorded moving between mainstem and tributary habitats during the transition from the summer dry season to the winter wet season. Such movement that connects summer and winter habitats may be particularly important for coho salmon, O. kisutch, because availability of overwintering habitat can limit freshwater survival for this species. Here, I describe basin-scale variability in the spatial pattern of fall movement for juvenile coho salmon between mainstem and tributary streams during the fall of 2002, 2003, 2004, and 2005. Juvenile coho salmon were tagged with a passive integrated transponder (PIT) and could be detected at five stationary detection sites, two located in perennial tributaries, two in intermittent tributaries, and one in the upper mainstem of the West Fork Smith River, Oregon.