George Washington Memorial Parkway

People seem to like numbers, and hierarchy, so here's a rundown of the leading units of the National Park System in terms of 2011 visitation. The first list combs through all 397 units in the system, while the second looks only at "national parks."

National Park Service officials and volunteer crews near the nation’s capital have their hands full these days, cleaning up after a flood.

NPS areas in and around the nation's capital will host or assist in special activities during the upcoming Memorial Day weekend, including an unusual concert and opportunity to view the city from a unique location.

Along with "parks," "seashores," "lakeshores" and "battlefields," the National Park System counts a number of "parkways" that fall under the jurisdiction of the National Park Service. Though most are incredibly scenic byways, there also are two major metropolitan arterials in this collection.