High Quality Content by WIKIPEDIA articles! Oxon Hill is part of the Oxon Hill-Glassmanor census-designated place (CDP) in southern Prince George`s County, Maryland, United States. Oxon Hill is a suburb of Washington, DC located southeast of the downtown district and east of Alexandria, Virginia. It is the home of the new 300-acre (1.2 km2) National Harbor development on the shore of the Potomac River .