In cooperation with the City of Durham Public Works Department Stormwater Division, the U.S. Geological Survey (USGS) conducted a study to evaluate whether alternate monitoring strategies that incorporated samples collected across an increased range of streamflows would improve nutrient load estimates for Ellerbe and Sandy Creeks, two small, highly urbanized streams in the City of Durham, North Carolina. This data release provides the associated datasets described in the Scientific Investigations Report, "Assessment of Nutrient Load Estimation Approaches for Small Urban Streams in Durham, North Carolina". Water-quality and streamflow data collected between January 2009 and December 2020 were used to develop instream nutrient-load models using the U.S. Geological Survey R-LOADEST program (Runkel and others, 2004; Runkel, 2013; Lorenz and others, 2017). The datasets contain water-quality data, streamflow data, input files for model calibration and prediction, and output files for model diagnostic and load estimation results. This data release contains 13 files: 1. "Ellerbe_water_quality_data.csv": This file contains water-quality data for samples collected by the City of Durham and USGS at Ellerbe Creek. 2. "Sandy_water_quality_data.csv": This file contains water-quality data for samples collected by the City of Durham and USGS at Sandy Creek. 3. "Ellerbe_streamflow_data.csv": This file contains USGS daily mean streamflow data for Ellerbe Creek. 4. "Sandy_streamflow_data.csv": This file contains USGS daily mean streamflow data for Sandy Creek. 5. "Ellerbe_input_calibration.zip": This zipped file contains eight individual model calibration input .csv files for nutrient load testing scenarios for Ellerbe Creek. 6. "Sandy_input_calibration.zip": This zipped file contains ten individual model calibration input .csv files for nutrient load testing scenarios for Sandy Creek. 7. "Ellerbe_input_prediction.zip": This zipped file contains four individual model prediction input .csv files for nutrient load testing scenarios for Ellerbe Creek. 8. "Sandy_input_prediction.zip": This zipped file contains five individual model prediction input .csv files for nutrient load testing scenarios for Sandy Creek. 9. "Ellerbe_model_diagnostic_results.csv": This file contains the diagnostic results for all nutrient regression models examined for Ellerbe Creek. 10. "Sandy_model_diagnostic_results.csv": This file contains the diagnostic results for all nutrient regression models examined for Sandy Creek. 11. "Ellerbe_load_estimation_results.csv": This file contains the estimated load results for all nutrient regression models examined for Ellerbe Creek. 12. "Sandy_load_estimation_results.csv": This file contains the estimated load results for all nutrient regression models examined for Sandy Creek. 13. "Readme.pdf": This document describes the datasets compiled for assessing nutrient load estimation approaches for Ellerbe and Sandy Creeks in the City of Durham, North Carolina.