<p>This study examines the anthropogenic influence on biogenic organosulfate formation at an urban site in Atlanta, GA in the Southeastern United States. Organosulfates were analyzed in fine particulate matter (PM<sub>2.5</sub>) collected during August 2015 in Atlanta using hydrophilic interaction liquid chromatography (HILIC), tandem mass spectrometry (MS/MS), and high-resolution time-of-flight (ToF) mass spectrometry. By their MS/MS response, 32 major organosulfate species were identified, selected species were quantified, and other species were semi-quantified using surrogate standards. Organosulfates accounted for 16.5 % of PM<sub>2.5</sub> organic carbon (OC). Isoprene-derived organosulfates were the most abundant, dominated by methyltetrol sulfate which accounted for 12.6 % of PM<sub>2.5</sub> OC. Together, the isoprene-derived organosulfates accounted for the majority of the isoprene-derived secondary organic aerosols (SOA) that had been previously observed in Atlanta, but had not been identified at the molecular level. Other major species included seven monoterpene-derived organosulfates, five diesel and/or biodiesel-derived organosulfates, and three new organosulfates that are also expected to derive from isoprene. Organosulfate species and concentrations in Atlanta were compared to those in a rural forested site in Centreville, AL during summer 2013, which were also dominated by isoprene-derived organosulfates. In Atlanta, isoprene-derived organosulfate concentrations were two to six times higher and accounted for twice as much OC. The greatest enhancement in concentration was observed for 2-methylglyceric acid sulfate, a tracer for isoprene high-NO<sub>x</sub> SOA. The isoprene-derived organosulfates indicated a stronger influence of NO<sub>x</sub> in Atlanta compared to Centreville. Overall, these results suggest that SOA in the Southeastern US can be reduced by controlling NO<sub>x</sub> and SO<sub>2</sub> emissions from fossil fuel combustion. This study gives insights into the major organosulfate species that should be targets for future measurements in urban environments and standard development.</p>