The Seneca Falls Convention of 1848 advertised itself as "a convention to discuss the social, civil, and religious condition and rights of woman" and is considered to be the first women's rights convention in the United States. When Seneca Falls offered a postmark to commemorate a 19-kilometer run, celebrating women's rights and the 19th Amendment, it seemed a fitting occasion to honor honor Susan B. Anthony.
While not present at the 1848 convention, Susan B. Anthony grew to be a tireless advocate for women's suffrage, such that the Nineteenth Amendment – granting women the right to vote – was colloquially known at the time as the "Anthony Amendment". The amendment was finally ratified in 1920, in spite of fierce resistance by some politicians, fully seventy-two years after the Seneca Falls Convention (and fourteen years after Anthony's death).
This cover features a processed photograph of Susan B. Anthony's house in Rochester, New York, where she lived for forty years, and where she was arrested after attempting to vote in the 1872 Presidential election (the house was declared a National Historic Landmark in 1965).
In the lower-left is a photograph from the National Archives of the original joint resolution of Congress ratifying the amendment. It reads, simply: "The right of citizens of the United States to vote shall not be denied or abridged by the United States or by any State on account of sex". For the cover, I added a digital frame to the document.
The cover bears one 50¢ Susan B. Anthony stamp (Scott #1051) from 1955 and is cancelled with the "19th Amendment Station" pictorial postmark from Seneca Falls, New York on May 7, 2016.
More on Susan B. Anthony: https://en.wikipedia.org/wiki/Susan_B._Anthony
More on the Seneca Falls Convention: https://en.wikipedia.org/wiki/Seneca_Falls_Convention