Sidescan-sonar imagery and bathymetric data collected in 2004 as part of NOAA survey H11322, along with seismic-reflection data collected by the USGS in 1980, are used to interpret the sea-floor geology and sedimentary environments in western Rhode Island Sound. Bathymetric highs in the study area tend to be associated with moderate to high backscatter, sand waves, and, on the western bathymetric high, erosional outliers. The southern edge of the eastern bathymetric high is flanked by scarps. The bathymetric highs tend to be composed of glacial drift at the surface, which in the east includes glaciolacustrine sediments. Sedimentary environments characterized by erosion or nondeposition and coarse-grained bedload transport are located on bathymetric highs and sedimentary environments characterized by sorting and reworking processes are located on their flanks. Bathymetric lows tend to have low backscatter and are commonly composed of fluvial sediments. Sedimentary environments characterized by fine-grained deposition are located in deeper parts of the study area. Trawl marks also tend to be found in the bathymetric lows. Boulders are scattered throughout the study area and dredge spoils are located in the southwest.