A land cover map of the Chesapeake Bay Watershed plus the non-watershed components of counties that intersect the Watershed. The map has 17 cover classes modified from the Anderson Level II system. Landsat remotely sensed data and additional thematic data bases were used to create the map. A decision-tree classification was used, together with ad hoc algorithms to improve local accuracies. Landsat 7 ETM+ data were acquired for three seasons. The spatial accuracy is nominally 30m, but accuracy increases rapidly at larger minimum mapping units and, as a general rule, the map should not be used below 1ha (100m x 100m) resolution. The map extends beyond the watershed but has not been validated outside the watershed boundary and the intersecting counties.