Water and gas chemistry data from: Mariner, R.H., Evans, W.C., and Young, H.W., 2006. Comparison of circulation times of thermal waters discharging from the Idaho batholith based on geothermometer temperatures, helium concentrations, and 14C measurements. Geothermics 35(1), pg. 3-25, https://doi.org/10.1016/j.geothermics.2005.08.002. Water chemistry data was digitized for 42 samples. Reported attributes include: Sample name, Type, Collection date, Reported latitude, Reported longitude, State, Latitude, Longitude, Location resolution, Location error, Elevation, Source, Temperature, pH, Calcium (Ca), Chloride (Cl), Fluoride (F), Alkalinity as bicarbonate (HCO3), Potassium (K), Magnesium (Mg), Sodium (Na), Nitrate (NO3), Silica (SiO2), Sulfate (SO4), Cations, Anions, Reported total dissolved solids, Total dissolved solids, Charge balance, Isotopic composition of hydrogen (Delta 2H), Isotopic composition of oxygen in water (Delta 18O H2O), Isotopic composition of carbon (Delta 13C), 14C, Author comment, Digitizer comment. Gas chemistry data was digitized for 27 samples. Reported attributes include: Sample name, Type, Reported latitude, Reported longitude, State, Latitude, Longitude, Location resolution, Location error, Temperature, Total gas, Argon (Ar), Methane (CH4), Carbon dioxide (CO2), Helium (He), Nitrogen (N2), Oxygen (O2), Dissolved argon (Ar dissolved), Dissolved helium (He dissolved), Dissolved nitrogen (N2 dissolved), Dissolved oxygen (O2 dissolved), Author comment, Digitizer comment. Data was digitized from Tables 1, 2, 3, 4, and 5. The following tables were not digitized: Table 6: Water ages based on geothermometry, carbon-14, and dissolved helium. Table 7: Distribution of geothermal system temperatures for the Idaho batholith based on the Na–K–Ca geothermometer. Table 8: Delta 13C values of mineral carbonate from the Idaho batholith. Table 9: Potential age errors for geothermometer, 14C, and helium methods.