This U.S. Geological Survey (USGS) Data Release provides salinity and density data collected at Great Salt Lake (GSL), Utah monitoring locations during 2021–2022. Temperature, specific conductance, and dissolved oxygen were collected using an In-Situ AquaTROLL 600. Sample density was measured using an Anton Paar DMA 35Ex at 5° increments between 5° and 40° C. Practical salinity was measured at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science using a Guideline Salinometer. These data were used to validate the equation of state for Great Salt Lake at salinities higher than the established range, 23–182 g/L (Naftz, et al, 2011). Data supports increasing the upper density range from 1.145 g/cm3 to 1.214 g/cm3. This increase allows for salinity monitoring up to 270 g/L and encompasses all (north and south arm) GSL waters.