This data release provides estimates of annual agricultural use of pesticide compounds in counties of the conterminous United States, for years 2013-17, compiled by means of methods described in Thelin and Stone (2013) and Baker and Stone (2015). For all States except California, U.S. Department of Agriculture county-level data for harvested-crop acreage were used in conjunction with proprietary Crop Reporting District-level pesticide-use data to estimate county-level pesticide use. Where Crop Reporting District data were not available or were incomplete, estimated pesticide-use values were calculated with two different methods, resulting in a low and a high estimate based on different assumptions about missing survey data (Thelin and Stone, 2013). Pesticide-use data for California for 2013-17 were obtained from the online Department of Pesticide Regulation Pesticide Use Reporting (DPR–PUR) database (California Department of Pesticide Regulation, variously dated). The California county data were appended after the estimation process was completed for the rest of the Nation. Estimates of annual agricultural pesticide use are provided as downloadable, tab-delimited files, organized by compound, year, state Federal Information Processing Standard (FIPS) code, county Federal Information Processing Standard code, and amount in kilograms (kg). This data release contains estimates of annual agricultural pesticide use for 2013-17 along with associated metadata. This data release is a continuation of the 1992-2009 pesticide-use estimates reported by Stone (2013) and the 2008-2012 pesticide-use estimates reported by Baker and Stone (2015). Tables of annual agricultural pesticide use estimates for 1992-2012 are available for download on the Pesticide National Synthesis Project (PNSP) webpage: https://doi.org/doi:10.5066/F7NP22KM. Beginning 2015, the provider of the surveyed pesticide data used to derive the county-level use estimates discontinued making estimates for seed treatment application of pesticides because of complexity and uncertainty. Pesticide-use estimates prior to 2015 include estimates with seed treatment application. Data for some compounds were missing from the version 1 estimates. Pesticide use estimates for compounds with missing data have been updated in version 2.0. First posted November 26, 2019 Revised May 27, 2020, ver. 2.0 References cited: Baker, N.T., and Stone, W.W., 2015, Estimated annual agricultural pesticide use for counties of the conterminous United States, 2008–12: U.S. Geological Survey Data Series 907, 9 p., accessed July 12, 2015, at https://doi.org/10.3133/ds907. California Department of Pesticide Regulation, variously dated, Pesticide use reporting (PUR): California Department of Pesticide Regulation Pesticide Use Reporting (PUR), Pesticide Use Report Data (PUR archives pur2013.zip, pur2014.zip, pur2015.zip, pur2016.zip, pur2017.zip), accessed June 26, 2019, at http://www.cdpr.ca.gov/docs/pur/purmain.htm. Stone, W.W., 2013, Estimated annual agricultural pesticide use for counties of the conterminous United States, 1992–2009: U.S. Geological Survey Data Series 752, 1-p. pamphlet, 14 tables, accessed July 12, 2015, at http://pubs.usgs.gov/ds/752/. Thelin, G.P., and Stone, W.W., 2013, Estimation of annual agricultural pesticide use for counties of the conterminous United States, 1992–2009: U.S. Geological Survey Scientific Investigations Report 2013–5009, 54 p., accessed July 12, 2015, at http://pubs.usgs.gov/sir/2013/5009/.