The U.S. Geological Survey (USGS), in cooperation with the National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the coastal sea floor. Bathymetry and sidescan-sonar imagery, originally collected by NOAA for charting purposes, provides a fundamental framework for research and management activities in Long Island Sound, shows the composition and terrain of the seabed, and provides information on sediment transport and benthic habitat. During October 2008 NOAA completed hydrographic survey H11251 offshore of Rocky Point, New York and during November 2009, bottom photographs and surficial sediment data were acquired as part of a ground-truth reconnaissance survey of this area. Interpretive data layers were derived from the multibeam echo-sounder and sidescan-sonar data and the ground-truth data used to verify them. For more information on the ground-truth survey see http://quashnet.er.usgs.gov/data/2009/09059/