In this project, we evaluated the potential for roadside ditches to transport and transform nitrogen (N) across mixed use, agricultural landscapes by coupling site-specific field measurements and a GIS-based modeling tool. We compared dissolved (NO3+NO2) and gaseous N (N2O) fluxes among three rural roadside ditches – 2 associated with active agricultural fields and one ditch draining a woodlot. Both ditches adjacent to ag fields were major conduits of dissolved nitrogen (with concentrations ranging from 10-40 mg/L and high flow rates), whereas the woodlot ditch was frequently dry and had nitrate concentrations of less than 0.1 mg/L. Nitrous oxide fluxes from the soils were present on all 7 sampling dates (May – late Sept), with the highest levels in the two ag ditch sites; however, flux rates varied substantially through time and among sites. Currently, no simple and cost-effective tools exist to estimate the impacts of roadside ditches on the entire interconnected network of streams and ditches in a watershed. In order to begin scaling up our site-specific field data to whole watersheds, and to aid in identifying “hot spots” for greenhouse gas production and N transport or removal, we developed a GIS-based toolset (Ditch Tools) that incorporates the specific effects of a watershed roadside ditch network into the hydrologic landscape using publicly available GIS data sets.