This dataset includes geological and geophysical data from petroleum wells located in the North Coles Levee Oil Field, Kern County, California. The purpose of this dataset is to describe groundwater salinity trends and the related geological controls. These data are used in an interpretive manuscript that characterizes a salinity inversion (lower-salinities found below higher-salinities) in North Coles Levee Oil Field. The geophysical data were primarily extracted by selecting data points from scanned well logs; however, some of these logs were digitized in their entirety. The geological data were extracted by interpreting select geologic formations from geophysical well logs relevant to the accompanying manuscript. These datasets were compiled and analyzed as part of the California State Water Resources Control Board Oil and Gas Regional Monitoring Program and the U.S. Geological Survey California Oil, Gas, and Groundwater (COGG) program.