This document proposes a Total Maximum Daily Load (TMDL) for phosphorus in the Sassafras River. The Sassafras River drains to the Chesapeake Bay and is part of the Upper Eastern Shore Tributary Strategy Basin. The Sassafras River was identified on the States 1996 list of Water Quality Limited Segments (WQLSs) as impaired by nutrients and suspended sediments. The suspended sediment impairment will be addressed at a later date. Limits are established for phosphorus because phosphorus is the nutrient that limits algal growth. The water quality goal of this TMDL is to reduce high chlorophyll a concentrations (a surrogate for algal blooms) and to maintain the dissolved oxygen criterion at a level where the designated uses for the Sassafras River will be met. The TMDL was determined using the WASP5.1 water quality model. The modeling work investigated seasonal variations indicating that phosphorus causes excessive algal growth during low flow and average flow conditions. Therefore, a loading cap on phosphorus entering the Sassafras River is established for low-flow and average annual flow conditions. This will ensure that loads during the higher flow seasons do not contribute to impairments observed during the low flow seasons.