Falls (Lock 20) and Swain's Lock (Lock 21). A second phase of work at the Paw Paw tunnel started on May 13, 2019. Today Extent The park includes nearly in a strip along the Potomac River. A small portion of the towpath near Harpers Ferry National Historical Park doubles as a section of the Appalachian Trail. The canal begins at its zero mile marker (accessible only via Thompson's Boat House), directly on the Potomac, opposite the Watergate complex. Author John Kelly, writing for The Washington Post in 2004, suggested that the name of the Watergate complex may derive from its location directly adjacent to the canal's zero milepost, where to this day, the canal's large wooden gate sits directly on the Potomac and adjacent to the complex. Kelly wrote, a canal lock is "quite literally, a water gate." In Allegany County, Maryland, the park includes the Western Maryland Railroad Right-of-Way, Milepost 126 to Milepost 160, listed on the National Register of Historic Places in 1981. Flooding continues to threaten historical structures on the canal and attempts at restoration. The Park Service has re-watered portions of the canal, but the majority of the canal does not have water in it. Usage Varied in its geography, the canal and its towpath along with the adjacent Potomac offers activities including running, hiking, biking, fishing, boating and kayaking, as well as rock climbing in certain locations. The Canal also offers a variety of wildlife and birdwatching opportunities. The seven National Park Service visitor centers have displays and interpretive exhibits on the history of the canal. The park offers rides on two reproduction canal boats — the Georgetown and the Charles F. Mercer (named after the first president of the Canal corporation, and not the first boat on the canal named Charles F. Mercer) — during the spring, summer and autumn. The boats are pulled by mules, and park rangers in historical dress work the locks and boat while presenting a historical program. Chesapeake and Ohio Canal National Historical Park receives around five million recreation visits annually. Access through the Great Falls Tavern Visitor Center requires payment, but access anywhere else in the park is free. In January 2015, the National Park Service proposed adding entrance fees to virtually all access points along the towpath; the proposal was rescinded in February, amid backlash from communities along the canal. On February 9, 1963, Robert F. Kennedy