Nitrogen inputs to Rhode Island rivers contribute to eutrophication in Narragansett Bay. Rivers account for more than half of the total nitrogen inputs to the bay, and a significant proportion of the nitrogen carried by rivers is anthropogenic. Therefore, studying nitrogen inputs to rivers can be useful to determine how to address anthropogenic nitrogen inputs to the bay. I used export coefficient modeling and empirical load estimation to quantify nitrogen inputs in three Rhode Island watersheds with contrasting land use. I compared the two load estimation methods to evaluate their accuracy, using empirical data from storm sampling to verify the export coefficient model results. I used the results of the models to determine which sources contribute the most to the total nitrogen loads, in the three study site watersheds and in the entire Narragansett Bay watershed. I concluded that the two estimation methods are fairly consistent with each other, although there are significant sources of uncertainty. The models suggest that the most important anthropogenic sources of nitrogen for rivers draining to Narragansett Bay are sewage and urban runoff from residential areas. Agricultural inputs of nitrogen are much less important in Rhode Island, despite the public perception of agriculture as an important cause of eutrophication.