California's Central Valley ranges from the mountain fronts toward a central trough, mainly defined by the San Joaquin and Sacramento Rivers, and the relative distance from trough to valley edges is of interest. This data release provides supplemental data for the USGS Professional Paper 1766, titled Groundwater Availability of the Central Valley Aquifer, California and provides geographic information systems (GIS) datasets containing this relative distance grid and supporting data. Included in this data release are shapefiles used to define the Central Valley study area, the Central Valley trough, and a relative distance grid that may be used to spatially define other GIS data into zones between the edge of the Central Valley and the trough. These relative distances were calculated as part of groundwater availability study documented in the Professional Paper, for a 30 x 30-meter cell size grid for the Central Valley. The edge of the valley was represented by the boundary of the valley fill deposits and was assigned an arbitrary value of 1000. The valley trough was represented by the division of California's Department of Water Resource's groundwater subbasins from west to east, from the intersection of Enterprise, Anderson, and Millville subbasins in the north to the Westside and Kings subbasins in the south with an extended line through historic lakes Tulare, Buena Vista, and Kern. This valley trough was assigned a value of 0 which included the boundaries of the historic lakes.