This part of DS 781 presents data for bathymetric contours for several seafloor maps of the Offshore of Gaviota Map Area, California. The vector data file is included in "Contours_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. Bathymetry contours of the Offshore of Gaviota map area in southern California was generated from acoustic-bathymetry data collected largely 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. In addition, bathymetric-lidar data was collected in the nearshore area by the U.S. Army Corps of Engineers (USACE) Joint Lidar Bathymetry Technical Center of Expertise in 2009 and 2010. These mapping missions combine to provide continuous bathymetric data from the shoreline to beyond the limit of California's State Waters. Bathymetric contours at 10-m intervals were generated from a modified 2-m-resolution bathymetric surface. The most continuous contour segments were preserved; smaller segments and isolated island polygons were excluded from the final output. Contours were smoothed using a polynomial approximation with exponential kernel algorithm and a tolerance value of 60 m. The contours were then clipped to the boundary of the map area.