Daughter of William Plumstead and Rebecca Kearney. Married to sometime Lt-Gov of New York, Andrew Elliot (d. 1797) of Greenwells, son of Sir Gilbert Elliot (d. 1766), Lord Minto, a colleague of Alexander Boswell's in the Court of Session. They had at least three daughters.
Boswell mentions her being present at a dinner party at John Trotter's in London on May 19, 1763. Boswell provides no further details about her, other than that she is American and married to Mr Elliot.