MassGIS has produced a statewide digital datalayer of the 32 major watersheds covering Massachusetts as defined by the USGS Water Resources Division and the MA Water Resources Commission. Unlike the Major Basins layer (also available throught the MIT Geodata Repository), the watersheds in this layer extend beyond the state boundary to include the full extent of either the full watershed or a full USGS sub-basin. An index map of this data is available at http://www.state.ma.us/mgis/ix_wat.htmMassGIS is maintaining this datalayer.