Mary, also called "Polly" was born at Balltgrowan towland, Ballynure parish, Antrim County, North Ireland, Sept 15, 1759, the 1st of 10 children of John Sitlington (who emigrated to Augusta County, Virgina, 1774 & his 2nd wife (name not known);
‌Mary and John were married in a religious ceremony on September 13th, 1763 in ,Augusta,VA.1 They had five sons and a daughter, named John, Isaac, Hugh, David, Thomas and Jane.