Neponset River Greenway MapOpen year-round, dawn to dusk. The Lower Neponset River Trail follows the path of a former railroad bed along the shore of the Neponset River. Traversing a rich variety of historical and ecological contexts, the 2.4 mile path serves to link the Neponset area to the larger network of DCR trails. The trail currently stretches from the historic Port Norfolk neighborhood in Dorchester, through Pope John Paul II Park , across Granite Avenue through the Neponset Marshes, and through the Lower Mills area to Central Avenue in Milton. In the future connections are planned from Central Avenue to Mattapan and from Port Norfolk to Commercial Point, linking to existing trails to Castle Island.