federal burial ground, NE Virginia, administered by the U.S. Army. The site, on the Potomac R. across from Washington, D.C., occupies more than 170 ha (420 acres) and contains more than 200,000 graves. Most of those interred here were members of the U.S. Armed Forces killed in battle. Among the monuments on the grounds are the Tomb of the Unknowns (dedicated 1932; see UNKNOWN SOLDIER,), the Arlington Memorial Amphitheater (1920), the Challenger Space Shuttle Memorial (1987), and Arlington House, also known as the Custis-Lee Mansion. Just N of the cemetery is the U.S. Marines Corps War Memorial, commemorating the raising of the flag at Iwo Jima during World War II.

In 1861, after the outbreak of the American Civil War, the mansion and grounds were confiscated from the owner, the Confederate general Robert E. Lee, by the Union government. The house was converted to a hospital, and in 1864 the grounds were first used as a military cemetery. After the Civil War the U.S. Supreme Court ruled that the house was the property of George Washington Custis Lee (1832–1913), the general's son. He sold it to the federal government in 1883. Famous Americans buried in the cemetery include the political leader and editor William Jennings Bryan; Presidents William H. Taft and John F. Kennedy; Kennedy's wife, Jacqueline Bouvier Kennedy Onassis, and his brother, political leader Robert F. Kennedy; Generals Philip H. Sheridan, John J. Pershing, and George C. Marshall; the army surgeon and bacteriologist Maj. Walter Reed; the explorer Adm. Robert E. Peary; the civil rights leader Medgar Evers; and the boxer Joe Louis. The cemetery receives more than 4 million visitors annually.