We report results from the first broadscale U.S. study to investigate the link between an ecotype and its intrinsic potential to act as a source of ice nucleating particles (INPs). INPs in boundary layer air above diverse natural and agricultural landscapes (including during four harvests) across the West Central United States were quantified and characterized. INP concentrations were generally higher above agricultural landscapes, where harvesting acted as both a strong point source of high-temperature INPs and, when occurring across a region, to raise ambient INP concentrations. Across all landscapes, biological/organic INPs typically dominated the INP composition to at least -20Â°C. The outcome of these studies will be improved understanding of continental INP sources, including parameterization of inorganic, organic and biological INPs for use in numerical modeling studies at cloud, regional and climate scales.