Daughter of Sir Michael Stewart (ca. 1712-1796), 3rd Baronet of Greenock and Blackhall, and Helen (or Helenora) Houstoun (d. 1746). Sister of Houstoun Stewart-Nicholson. Married (1764) to William Maxwell. The couple had at least 6 children.
During the early part of his stay in Holland (1763), Boswell seriously considered marrying Margaret Stewart. In a letter to Temple of September 23, 1763, he writes "Stewart's sister is sensible, amiable, has been several winters in London, is perfectly accomplished. She is not handsome, but is extremely agreeable and what you would calla a woman of fashion. She and I were always good friends; and when I was in Scotland, she was the only woman I could think of for a wife." On November 9, however, he had given up the idea of marrying any time soon, as he told Temple in another letter. Still, when he received news of Stewart's marriage to his cousin William Maxwell just 5 months later, it galled him.1
- 1Boswell in Holland, April 13, 1764