Williamson was born on July 12, 1757, to AlexanderWilliamson, secretary to James Hope Johnstone, third Earl of Hopetoun, and his wife Christina Robertson, who lived on the estate of Balgray in Applegarth and Sibbaldbie Parish, Dumfriesshire.
Williamson attempted without success to induce a group of Scottish highlanders, led by Donald Stewart, to settle on the Pulteney lands.
Williamson traveled to Johnstown to meet the Scots, and he encouraged them to settle at Big Springs, which he later named Caledonia.
Williamson had five children and they were all actively involved in the Scottish Home and the Society.
Williamson died, the family presented a check to the Saint Andrew Society and established a fund for the hiring of professional nurses to care for the residents.
Her father, Daniel Williamson, from Cromarty, Scotland and her mother, Margaret Ray, from County Down, Ireland met in Washington Co. NY and were married there early in the 19th century.