These metadata sets present the comprehensive geochemical composition of solid and water samples from the site of a 11.4ML (million liters) wastewater spill discovered in January, 2015. Analyses of a pipeline sample (analyses of select analytes), supplied by the North Dakota Department of Health are also included. The spill was near Blacktail Creek, north of Williston, ND. The leak was from a pipeline located approximately 70m from Blacktail Creek. The creek flows 17km before entering the Little Muddy River, a tributary to the Missouri River. The study included samples collected in waters upstream and downstream from Blacktail Creek in February and June 2015, June 2016, and June 2017. These data sets include field measurements of pH, temperature, dissolved oxygen, sulfide and specific conductance; laboratory analyses of major ions, trace elements, alkalinity, ammonium, delta deuterium and delta oxygen-18 of water, strontium and radium isotopes; non-volatile dissolved organic carbon (NVDOC), low molecular weight organic acids (LMWOA), and hydrocarbons at surface-water sites. Geomorphic characteristics and watershed similarity tables are included. Sediments were collected in February and June 2015, June 2016, and June 2017 for analysis of carbon, nitrogen, radium and uranium isotopes and extractable ammonium, strontium, and barium. Duplicate water samples and field blanks were collected during each sampling campaign. Two groundwater seep sites were sampled in June 2017 for a select number of analytes. This data release includes twelve data tables provided in two zip folders both as Excel (.xlxs) and machine readable 'comma-separated values' format (.csv): 1) data dictionary; 2) descriptions of sampling site locations; 3) summary of field sampling procedures; 4) field measurements, NVDOC, ammonium, alkalinity, strontium isotopes, deuterium and oxygen-18 isotopes, LMWOA and hydrocarbons; 5) concentrations of major anions, cations and trace elements; 6) radiochemistry for sediment samples; 7) extractable ammonium, barium, and strontium concentrations from sediment samples; 8) measured and computed composition of water extracts and pore water concentrations; 9) carbon and nitrogen from sediments; 10) geomorphic characteristics; 11) watershed similarity analysis; and 12) Quality Assurance/Quality Control (QA/QC). This metadata publication’s citation will be added to “Geochemical Indicators of Oil and Gas Wastewater can Trace Potential Exposure Pathways Following Releases to Surface Waters”, Cozzarelli et al., USGS ScienceBase associated manuscript in review, summer of 2020.