Description: These data were developed to identify benthic habitat types and to map their distribution within the Northwest Atlantic Marine region. These data were derived by starting with a conventional habitat classification strategy, with classes constructed using combined physical factors-depth, seabed form, and substrate type. Biological data was then overlaid and analyzed using a quantitative cluster analysis to identify distinct species groups, followed by classification and regression tree analysis to identify the threshold values for each physical factor that best predict occurrences for all species groups. Finally, GIS analysis methods were used to produce data which are the three-way combination of depth, sediment grain size and seabed form based on the ecological thresholds revealed by the organism relationships. The thresholds used for depth, grain size and seabed form to define the benthic habitats were extracted directly from the organism data. This step was critical in ensuring that the benthic habitats represent truly different environments as perceived by the benthic macrofauna. Development of these data was made possible by access to over forty years of data from the unparalleled sampling effort of the Northeast's benthic invertebrate fauna by NOAA's National Marine Fisheries Service (NMFS): Northeast Fisheries Science Center. Primary data sources on physical factors were a comprehensive bathymetry grid from NOAA's National Geophysical Data Center and substrate data from usSEABED, a collaborative product of the USGS and other partners.