This data set was acquired with a Kongsberg model EM120 multibeam sonar system during Nathaniel B. Palmer expedition NBP0803 conducted in 2008 (Chief Scientist: Dr. Philip Bart). These data files include Sidescan, Swath Bathymetry, Acoustic Backscatter data and were processed at sea using the open source MB-System multibeam sonar processing software. Data were acquired as part of the project(s): Ross-Sea outer continental shelf morphology and near-surface stratigraphy: Quaternary ice-sheet grounding-zone migrations and stratigraphy: Quaternary ice-sheet grounding-zone migrations and the LGM dilemma., and funding was provided by the U.S. National Science Foundation.