John Lovet MacTavish (c. 1787 – June 21, 1852)[1] was a Scots-Canadian heir to the North West Company[2] and diplomat.

[1][5] After his wedding to Emily Caton of Maryland, they lived at Brooklandwood estate in the Green Spring Valley of Baltimore County, where Emily had been born,[6] before moving to 1,000 acres of the "finest farm land in Howard County,[7] given as a wedding gift from his wife's grandfather and named "Folly Quarter" after the MacTavish family estate in Scotland.

[8] Emily's maternal grandfather was Charles Carroll of Carrollton, the only Catholic and the longest-surviving signer of the Declaration of Independence.

Marianne marrying first Robert Patterson (brother of Elizabeth Patterson, the first wife of Napoleon's younger brother Jérôme Bonaparte) and second Richard Wellesley 1st Marquess Wellesley and Lord Lieutenant of Ireland (older brother of the Duke of Wellington); Bess marrying Sir George Strafford, 8th Baron Strafford of Costessey Hall in Norfolk, England; and Louisa marrying first Sir Felton Hervey-Bathurst, 1st Baronet and second Francis D'Arcy Osborne, Marquess of Carmarthen (the future 7th Duke of Leeds).

His widow died on January 26, 1867, at Folly Quarter and was interred with MacTavish at Green Mount Cemetery in Baltimore, Maryland.