AbstractMultiple species of the genusDinophysisproduce diarrhetic shellfish toxins (okadaic acid andDinophysistoxins,OA/DTXsanalogs) and/or pectenotoxins (PTXs). Only since 2008 haveDSPevents (illnesses and/or shellfish harvesting closures) become recognized as a threat to human health in theUnited States. This study characterized 20 strains representing five species ofDinophysisspp. isolated from threeUScoastal regions that have experiencedDSPevents: the Northeast/Mid‐Atlantic, the Gulf of Mexico, and the Pacific Northwest. Using a combination of morphometric andDNA‐based evidence, seven Northeast/Mid‐Atlanticisolates and four Pacific Northwest isolates were classified asD. acuminata, a total of four isolates from two coasts were classified asD. norvegica, two isolates from the Pacific Northwest coast were identified asD. fortii,and three isolates from the Gulf of Mexico were identified asD. ovumandD. caudata. Toxin profiles ofD. acuminataandD. norvegicavaried by their geographical origin within theUnited States. Cross‐regional comparison of toxin profiles was not possible with the other three species; however, within each region, distinct species‐conserved profiles for isolates ofD. fortii,D. ovum, andD. caudatawere observed. Historical and recent data from various State and Tribal monitoring programs were compiled and compared, including maximum recorded cell abundances ofDinophysisspp., maximum concentrations ofOA/DTXsrecorded in commercial shellfish species, and durations of harvesting closures, to provide perspective regarding potential forDSPimpacts to regional public health and shellfish industry.