Contains watershed boundaries for most ponds and rivers in Maine, based on USGS 1:24,000 scale topography. Drainage boundaries were determined using the 1:24,000 scale contours and were delineated on mylar copies of these maps by USGS staff in Augusta, ME in 1989. The mylars were digitized by Maine Geological Survey (MGS) in 1990 for the Maine Low-Level Radioactive Waste Authority. In 1993 MEGIS staff added the 1:24,000 coastline to this cover to close the coastal drainage. Divides were delineated on many coastal peninsulas to facilitate the selection of drainages for coastal embayments. Preliminary polygon coding was also begun at this time. At present the USGS's 8-digit Hydrologic Unit Code (HUC) has been added to all polygons. Extensive additional coding was done by DEP staff to delineate MIDAS numbers for watersheds, river drainages, and correct known errors.