This part of DS 781 presents data for the transgressive contours for the Point Conception to Hueneme Canyon, California, region. The vector file is included in "TransgressiveContours_PointConceptionToHuenemeCanyon.zip," which is accessible from https://doi.org/10.5066/F7891424. As part of the USGS's California State Waters Mapping Project, a 50-m grid of sediment thickness for the seafloor within the 3-nautical mile limit between Point Conception and Hueneme Canyon was generated from seismic-reflection data collected in 2014 (USGS activity 2014-632-FA) supplemented with outcrop and geologic structure (fault) information following the methodology of Wong (2012). Water depths determined from bathymetry data were added to the sediment thickness data to provide information on the depth to base of the post-LGM unit. This depth-to-transition layer was merged with a previously published depth-to-transition grid for the Santa Barbara Channel region (available at https://pubs.usgs.gov/ds/781/SantaBarbaraChannel/data_catalog_SantaBarbaraChannel.html). This polyline shapefile provides the depth-to-transition contours to accompany the grid layer. Reference Cited: Wong, F. L., Phillips, E.L., Johnson, S.Y., and Sliter, R.W., 2012, Modeling of depth to base of Last Glacial Maximum and seafloor sediment thickness for the California State Waters Map Series, eastern Santa Barbara Channel, California: U.S. Geological Survey Open-File Report 2012-1161, 16 p. (available at https://pubs.usgs.gov/of/2012/1161/)