In the Northern Plains of Montana, North Dakota and Minnesota, a number of site-specific tools have been used to delineate nitrogen management zones. A three-year study was conducted using yield mapping, elevation measurements, satellite imagery, aerial Ektochrome® photography, and soil EC to delineate nitrogen management zones and compare these zones to residual fall soil nitrate. At most of the sites, variable-rate N was applied and compared with uniform N application. The site-specific tools compared were universal in their usefulness, although some tools described zone boundaries better at some locations than at others. It was also clear in the study that present N fertilizer recommendations do not adequately account for the specific N rates required by site-specific applications.