Aquatic systems in urban areas may receive enhanced nutrient inputs from the surrounding landscape. The landscape structure within watersheds is hypothesized to influence nitrogen flux into aquatic systems. In urban areas, impervious surfaces and vegetation may be the structural elements which control these inputs. It has been hypothesized that increased impervious surface cover increases discharge to urban streams, which may be correlated with increased nitrogen flux. On the other hand, vegetation slows water flow and retains nutrients on the landscape. Therefore, increases in vegetation cover are expected to decrease discharge and nutrient flux to the streams. To evaluate these hypotheses, we selected 12 sub-basins of the Baisman Run and Gwynns Falls watersheds which are located within Baltimore City and County and are in the Chesapeake Bay drainage area. The sub-basins range in size from 4 to 30 ha and differ in land cover. High-resolution aerial imagery was used to calculate percentage of buildings, coarse vegetation (trees and shrubs), fine vegetation (herbs and grasses), pavement, and bare soils. Nitrogen concentration and discharge was collected from each stream for 18 months. We used correlation and linear regression models to determine which land cover variables, or combinations of variables, best predict water quality. Suburban streams had greater nitrate concentration and flux rates than more urban sites, a difference that may be attributed to presence of septic systems in the less intensely developed sites. Results indicate that fine vegetation cover was the most important predictor of nitrogen concentration. At this scale, impervious surface cover was not a strong predictor of nitrogen concentration or flux. Infrastructure, not resolved by aerial photography, appeared to be an important factor for determining system behavior. An understanding of the relationship between landscape structure and nutrient flow will help to elucidate mechanisms of material flow, which may inform better management of nutrients in urban systems and help prevent nutrient export to sensitive waterways.