This 1796 portrait of Martha Washington by Gilbert Stuart, known as the "Athenaeum" portrait, hangs in the National Gallery in Washington DC.
"Gilbert Stuart painted this portrait of Martha Washington at the same time he did that of the president. Both paintings were, commissioned by the Washingtons. They were never completed, however, and, the artist kept them in his possession until his death. Although Stuart made many copies of the president's portrait, no other likeness of Martha Washington by Stuart is known to exist." -- National Portrait GalleryLike her husband an engraving of Stuart's Athenaeum Portrait of Martha appeared on the $1 bill. This1886 silver certificate made Martha Washington the first woman whose portrait was used on a U.S. bill.
And in 1896 the Athenaeum portraits of George and Martha were united on a $1 bill.