New York's freshwater wetlands maps only show the approximate location of the actual wetland boundary. They are not precise, regardless of how closely you zoom in on the map. The "check zone" is an area around the mapped wetland in which the actual wetland may occur. If you are proposing a project that may encroach into this area, you should check with your regional DEC office to make sure where the actual wetland boundary is. If necessary, they may have a biologist come out and perform a field delineation for you to help you avoid impacts in the wetland or the regulated 100-foot buffer zone.