The Neponset River Reservation in Boston, Massachusetts is dog-friendly. Extending from Milton to the Boston Harbor, this natural inlet is home to plenty of marshlands and freshwater wetlands. The 2-mile Quincy Riverwalk path is well worth taking Fido on for some walkies, with spectacular views of the estuary and the city of Boston. Dogs are welcome on a leash under six feet, as long as owners clean up after them to preserve the cleanliness of the waterways. Neponset River Reservation is open every day of the week from dawn until dusk.