During hydrocarbon production, water is typically co-produced from the geologic formations producing oil and gas. Understanding the composition of these produced waters is important to help investigate the regional hydrogeology, the source of the water, the efficacy of water treatment and disposal plans, potential economic benefits of mineral commodities in the fluids, and the safety of potential sources of drinking or agricultural water. In addition to waters co-produced with hydrocarbons, geothermal development or exploration brings deep formation waters to the surface for possible sampling. This U.S. Geological Survey (USGS) Produced Waters Geochemical Database, which contains geochemical and other information for 114,943 produced water and other deep formation water samples of the United States, is a provisional, updated version of the 2002 USGS Produced Waters Database (Breit and others, 2002). In addition to the major element data presented in the original, the new database contains trace elements, isotopes, and time-series data, as well as nearly 100,000 additional samples that provide greater spatial coverage from both conventional and unconventional reservoir types, including geothermal. The database is a compilation of 40 individual databases, publications, or reports. The database was created in a manner to facilitate addition of new data and correct any compilation errors, and is expected to be updated over time with new data as provided and needed. Table 1, USGSPWDBv2.3 Data Sources.csv, shows the abbreviated ID of each input database (IDDB), the number of samples from each, and its reference. Table 2, USGSPWDBv2.3 Data Dictionary.csv, defines the 190 variables contained in the database and their descriptions. The database variables are organized first with identification and location information, followed by well descriptions, dates, rock properties, physical properties of the water, and then chemistry. The chemistry is organized alphabetically by elemental symbol. Each element is followed by any associated compounds (e.g. H2S is found after S). After Zr, molecules containing carbon, organic 9 compounds and dissolved gases follow. Isotopic data are found at the end of the dataset, just before the culling parameters.