The Massachusetts coastal zone extends from the three-mile limit of the state territorial sea to 100 feet beyond the first major land transportation route encountered (a road, highway, rail line, etc.). In addition, all of Cape Cod, Martha's Vineyard, Nantucket, and Gosnold are included in the coastal zone. Although this area is the focus of the coastal program, CZM's concerns go beyond this narrow strip of land and sea. The coast can be affected by activities both farther inland and farther seaward. In fact, coastal watersheds (areas that drain into coastal waters) make up the entire eastern half of the state. Contaminants released to air, soil, or water in these watersheds can be picked up by rainfall and snow melt and carried over land, in rivers and streams, through the air, in groundwater, or through drainage systems to the coast. In addition, CZM is involved with managing large ocean areas, such as Stellwagen Bank and the Gulf of Maine. Human activities, such as fishing and shipping, and the release of contaminants into these ocean areas also affect the Massachusetts coast.