This data release provides borehole location and lithology information from selected boreholes in the East Mesa and surrounding areas of Imperial County, California. The area of focus includes parts of the Imperial, Ogilby, and Amos Valley groundwater basins. The purpose of the study is to estimate the future Total Dissolved Solids (TDS) concentration in groundwater pumped by the LCWPS into the All-American Canal. The borehole data included in this data release can be used to evaluate the hydrogeologic framework of the study area, and determine the geometry, extent, and physical characteristics of hydrogeologic materials within the aquifer system. Borehole location and lithology data were sourced from the California Department of Water Resources Online System of Well Completion Reports (OSWCR; California Department of Water Resources, 2021) as well as direct communication with California Department of Water Resources (California Department of Water Resources, 2024); the U.S. Bureau of Reclamation Final Environmental Impact Statement Geohydrology Appendix for the All-American Canal Lining Project (U.S. Bureau of Reclamation, 1994); well log archives from the U.S. Bureau of Reclamation Yuma Area Office (U.S. Bureau of Reclamation, 2023); the U.S. Geological Survey (USGS) Professional Paper Series number 486 chapter K (Loeltz and others, 1975); a USGS publication detailing the characterization of the groundwater system near the Lower Colorado Water Supply Project (Coes and others, 2015), geothermal well reports (Coplen and others, 1973; Elders and others, 1974), and geothermal wells from California Geologic Energy Management Division (CalGEM; California Department of Conservation, 2024).