Gridded bathymetry and sidescan-sonar imagery together cover approximately 37.3 square kilometers of sea floor in the vicinity of Edgartown Harbor, Massachusetts. Although originally collected for charting purposes during National Oceanic and Atmospheric Administration hydrographic survey H11346, these acoustic data, and the sea-floor stations and seismic-reflection lines subsequently occupied to verify them, 1) show the composition and terrain of the seabed, 2) provide information on sediment transport and benthic habitat, and 3) are part of an expanding series of studies that provide a fundamental framework for research and management (for example, windfarms, pipelines, and dredging) activities along the Massachusetts inner continental shelf.