This part of SIM 3306 presents data for the folds for the geologic and geomorphic map of the Offshore of San Gregorio map area, California. The vector data file is included in "Folds_OffshoreSanGregorio.zip," which is accessible from https://pubs.usgs.gov/ds/781/OffshoreSanGregorio/data_catalog_OffshoreSanGregorio.html. These data accompany the pamphlet and map sheets of Cochrane, G.R., Dartnell, P., Greene, H.G., Watt, J.T., Golden, N.E., Endris, C.A., Phillips, E.L., Hartwell, S.R., Johnson, S.Y., Kvitek, R.G., Erdey, M.D., Bretz, C.K., Manson, M.W., Sliter, R.W., Ross, S.L., Dieter, B.E., and Chin, J.L. (G.R. Cochrane and S.A. Cochran, eds.), 2014, California State Waters Map Series—Offshore of San Gregorio, California: U.S. Geological Survey Scientific Investigations Map 3306, pamphlet 38 p., 10 sheets, scale 1:24,000, https://doi.org/10.3133/sim3306. Folds were primarily mapped by interpretation of seismic reflection profile data (see field activities S-15-10-NC and F-2-07-NC). The seismic reflection profiles were collected between 2007 and 2010.