The more than 220-year-old oak had stood through the construction of Arlington House, the pre-Civil War home of General Robert E. Lee and the creation of the cemetery in 1864, officials said.
In the spring of 1963, officials said President John F. Kennedy visited Arlington House and remarked that the view was so magnificent that he could stay there forever. That November, the president was assassinated and his wife chose the hillside in front of Arlington House near the tree for his burial site.
In addition to the Arlington Oak, five other trees fell because of the heavy rain and a white oak near the Pan Am Flight 103 memorial was uprooted.
Officials said some gravestones are also being reset after sinking due to the excessive rain.