This part of DS 781 presents 2-m-resolution data collected by the U.S. Geological Survey in 2008 for the acoustic-backscatter map of the Offshore of Gaviota Map Area, California. The GeoTiff is included in "Backscatter_[USGS08]_OffshoreGaviota.zip," which is accessible from https://doi.org/10.5066/F7TH8JWJ. These data accompany the pamphlet and map sheets of Johnson, S.Y., Dartnell, P., Cochrane, G.R., Hartwell, S.R., Golden, N.E., Kvitek, R.G., and Davenport, C.W. (S.Y. Johnson and S.A. Cochran, eds.), 2018, California State Waters Map Series—Offshore of Gaviota, California: U.S. Geological Survey Open-File Report 2018–1023, pamphlet 41 p., 9 sheets, scale 1:24,000, https://doi.org/10.3133/ofr20181023. The acoustic-backscatter map of the Offshore of Gaviota map area in southern California was generated from acoustic-backscatter data collected by the U.S. Geological Survey (USGS) and by Fugro Pelagos Inc. Acoustic mapping was completed between 2007 and 2008 using a combination of 400-kHz Reson 7125, 240-kHz Reson 8101, and 100-kHz Reson 8111 multibeam echosounders, as well as a 234-kHz SEA SWATHplus bathymetric sidescan-sonar system. These mapping missions combined to collect acoustic-backscatter data from about the 10-m isobath to beyond the limit of California's State Waters.