Question: What development in Price George's County is located along the Potomac River?

Context paragraphs:
Oxon Hill-Glassmanor, Maryland: Oxon Hill-Glassmanor was a census-designated place (CDP) in Prince George's County, Maryland, for the 1990 and 2000 censuses.  The combination is arbitrary, and in the mind of most local people there are two separate communities: Oxon Hill and Glassmanor.  As of the 2010 census, Oxon Hill, National Harbor and Glassmanor were delineated as separate CDPs.

Seneca Quarry: Seneca Quarry is a historic site located at Seneca, Montgomery County, Maryland.  It is located along the Chesapeake and Ohio Canal on the north bank of the Potomac River, just west of Seneca Creek.  The quarry was the source of stone for two Potomac River canals: the Potowmack Canal (opened in 1802, and officially known as the Great Falls Skirting Canal) on the Virginia side of Great Falls; and the C&O Canal, having supplied red sandstone for the latter for locks 9, 11, 15 - 27, and 30, the accompanying lock houses, and Aqueduct No. 1, better known as Seneca Aqueduct, constructed from 1828 to 1833.

National Harbor, Maryland: National Harbor is a development along the Potomac River in Oxon Hill, Prince George's County, Maryland just south of Washington, D.C. near the Woodrow Wilson Bridge.  It originated as a 300 acre multi-use waterfront development.  The development was delineated as a census-designated place for the 2010 census, at which time its population was 3,788.

East Potomac Park: East Potomac Park is a park located on a man-made island in the Potomac River in Washington, D.C., in the United States.  The park lies southeast of the Jefferson Memorial and the 14th Street Bridge, and the Washington Channel lies between the park and the Potomac River.  Amenities in East Potomac Park include the East Potomac Park Golf Course, a miniature golf course, a public swimming pool (the East Potomac Park Aquatic Center), tennis courts, and several athletic fields (some configured for baseball and softball, others for soccer, rugby, or American football).  The park is a popular spot for fishermen, and cyclists, walkers, inline skaters, and runners heavily use the park's roads and paths.  A portion of Ohio Drive SW runs along the perimeter of the park.

List of plantations in West Virginia: Plantations that operated within the present-day boundaries of West Virginia were located in the counties of the Ridge-and-Valley Appalachians and in the Kanawha and Ohio River valley regions.  Beginning in the mid-to-late 18th century, members of the Washington family and other prominent Virginia families began to build elegant Georgian mansions on their plantations in the Ridge-and-Valley Appalachians region of present-day West Virginia.  Plantations initially developed in the counties lying within the Northern Neck Proprietary of Thomas Fairfax, 6th Lord Fairfax of Cameron within the Shenandoah Valley and South Branch Potomac River valleys.  Slavery as practiced through plantations in the American South was carried over from the plantations of the Piedmont and Tidewater regions of Virginia, where plantations had become the foundation of society and industry.  Following the French and Indian War, settlement and agricultural development continued unabated in the Shenandoah and South Branch Potomac valleys.  Early instances of western Virginia plantations with grand homes include the John Ariss-designed Harewood (1774) for George Washington's brother Samuel Washington and Happy Retreat (1780) built by Washington's younger brother Charles Washington, both of which are located near Charles Town in present-day Jefferson County.  In Hampshire County, Nicholas Casey constructed a Georgian mansion (1774) at his Wappocomo plantation, one of the first plantation houses of its kind in the South Branch Potomac River valley.

Potomac River: The Potomac River ( ) is located along the mid-Atlantic Ocean coast of the United States and flows into the Chesapeake Bay.  The river (main stem and North Branch) is approximately 405 mi long, with a drainage area of about 14,700 square miles (38,000 km).  In terms of area, this makes the Potomac River the fourth largest river along the Atlantic coast of the United States and the 21st largest in the United States.  Over 5 million people live within the Potomac watershed.

Featherstone National Wildlife Refuge: The Featherstone National Wildlife Refuge is a National Wildlife Refuge located along the Potomac River in Virginia, at the point where it meets Neabsco Creek.  The 325 acre of tidal marsh has been administered by the United States Fish and Wildlife Service since 1970; currently, it is part of the Potomac River National Wildlife Refuge Complex.  The refuge covers wetlands and woodlands, and has a railroad right-of-way bordering its western edge.  It is currently closed to the public, but has been considered as a possible portion of the route for the Potomac Heritage National Scenic Trail.

Doe Gully, West Virginia: Doe Gully is an unincorporated community along the Potomac River in Morgan County in the U.S. state of West Virginia's Eastern Panhandle.  Located along the old Baltimore and Ohio Railroad where it bisects a bend in the Potomac by way of the Randolph Tunnel, Doe Gully is only accessible by way of Doe Gulley Lane (West Virginia Secondary Route 18/2) from Orleans Road (West Virginia Secondary Route 18/1).  It is located southwest of Orleans Cross Roads.  The Chesapeake and Ohio Canal National Historical Park crosses the Potomac River onto the West Virginia side to Doe Gulley's west and it also lies directly across the river from it.  Like most of the old B&O railroad stations and their communities, Doe Gully is popular with railfans.

Potomac Creek: Potomac Creek is a 16.7 mi tidal tributary of the Potomac River in King George and Stafford counties, Virginia.  Potomac Creek's source lies between the communities of Glendie and Paynes Corner in Stafford County.  It empties into the Potomac River at Marlboro Point.  Potomac Creek forms as a dam to form Abel Lake.

Hightown, Virginia: Hightown is an unincorporated community at the crossroads of U.S. Route 250 and Virginia State Route 640 in Highland County, Virginia, United States.  Hightown is located approximately 3 mi northwest of Monterey, Virginia.  The community lies on the division of the James River and Potomac River watersheds, with the main source of the South Branch Potomac River to the north of Hightown along State Route 640 and the source of the Jackson River, a tributary of the James, south of U.S. Route 250 west of Hightown.  The roof of a barn owned by Jacob Hevener located near Hightown is said to have divided the two watersheds, with rain falling on one side of the roof flowing to the James and on the other to the Potomac.  The community was originally known as Heveners Store.

Supporting paragraphs: Oxon Hill-Glassmanor, Maryland National Harbor, Maryland
Answer: National Harbor