Three reports have been generated as products of the synthesis of historical biological data project of the Tampa Bay National Estuary Program (TBNEP): Distribution of Selected Fish Species in Tampa Bay, Database of Benthic Sampling Locations in Tampa Bay, and the current report, Oligohaline Areas in Tampa Bay Tributaries: Spatial Extent and Species Lists. A summary of the spatial extent of oligohaline (low salinity) habitats in Tampa Bay tributaries was planned as part of the synthesis of historical biological data project. Three salinity zones were identified for each of the four major freshwater tributaries to Tampa Bay: The Hillsborough River, Alafia River, Little Manatee River, and Manatee River. Salinity zones were defined as areas where salinity was never less than 10 ppt., sometimes less than 10 ppt., or always less than 10 ppt. Maps of salinity zones, including shoreline and aquatic vegetation, were prepared and submitted to TBNEP. In addition, lists were prepared of plant, benthic, and fish species collected by field studies within each salinity zone.