1799
February 22: Martha Washington's youngest granddaughter, Nelly, marries George Washington's nephew, Lawrence Lewis, at Mount Vernon on her step-grandfather's birthday.

November 14: Martha Washington's fourth great-grandchild, John Parke Custis Peter, is born.

November 27: A fifth great-grandchild, Frances Parke Lewis, is born at Mount Vernon, to Nelly and Lawrence Lewis.

December 14: George Washington dies at Mount Vernon after a short illness. Martha Washington, who remained with her husband throughout his illness makes the statement, "'Tis well….All is now over[.] I shall soon follow him! I have no more trials to pass through!" She was too distraught to attend the funeral on December 18th.

Martha Washington moves from the room she had shared with her late husband to a smaller room on the third floor of the mansion. She will never again enter either their bedroom or George Washington's study. Sometime during the next two years, she will burn almost all of the couple's correspondence, probably in an effort to retain their privacy.

1800
September: Mrs. Washington prepares her will and names four executors: her grandson, George Washington Parke Custis; two nephews, Julius B. and Bartholomew Dandridge; and Thomas Peter, the husband of her second granddaughter, Patty.

December 15: Mrs. Washington signs a deed of manumission to emancipate those Mount Vernon slaves who had belonged to George Washington. They are officially freed on January 1, 1801.

1801
August 19: Martha Washington's sixth great-grandchild, Martha Betty Lewis, is born at Mount Vernon.

November 18: A seventh great-grandchild, George Washington Parke Custis Peter, is born. Martha Washington will ultimately have twenty great-grandchildren.

1802
March 4: Mrs. Washington adds a codicil to her will, bequeathing the only slave she owns outright to her grandson, George Washington Parke Custis. In accordance with Virginia law, the remaining slaves at Mount Vernon, all of whom belonged to the estate of her first husband, Daniel Parke Custis, will be divided among her four grandchildren upon her death.

May 22: Martha Washington dies at Mount Vernon surrounded by friends, relatives, and slaves.