The only plantation in Fairfax Co., VA, that I know of that is connected with Martha Dandridge Custis Washington is:
It was owned by William Fitzhugh. Martha Custis Washington adopted two of her grandchildren, Nellie (Eleanor) Custis and George Washington Parke Custis. G.W.P.Custis married Mary Randolph, niece? ofWilliam Fitzhugh. The plantation was inherited by G.W.P.Custis's grandson, George Washington Custis Lee, called Custis by his family. He was the son of Mary Lee Custis Lee and her husband, Robert E. Lee.
Feel free to email me at firstname.lastname@example.org for more info. I am administrator of the MyFamily.com Descendants of Robert "King" Carter of Lancaster Co., VA 1663-1732