Radio telemetry was used to determine home ranges of 38 largemouth bass (Micropterus salmoides) from the tidal upper Chesapeake Bay in Maryland. Bass from opposite shores (Susquehanna = west, Northeast = east) were tagged from 1991-1993 and tracked for 4-15 months (1991-1995) depending on battery life. Mean home range of Susquehanna bass (246 ha, N = 16) was larger than non-migratory Northeast bass (119 ha, N = 18) but the difference was not significant. Mean home range (2140 ha) of 4 migratory Northeast bass that made an annual spawning migration across the Bay was significantly different than the mean home ranges for the Northeast, Susquehanna, and pooled groups (178 ha). Mean home range for all groups (119-2140 ha) was much higher than home range sizes reported in the literature for freshwater lakes and impoundments (0.01-21 ha). Our results suggest that observed differences in home range sizes between freshwater and tidal systems are related to tidal influence and/or some correlate in the habitat. As opposed to freshwater systems that generally provide a relatively stable and predictable environment, largemouth bass in tidal systems are influenced by daily, lunar, and seasonal tidal fluctuations, seasonal and weather related brackish water influx, and seasonal and storm event related freshwater inflow.