John Thomson Mason

John Thomson Mason (15 March 1765 – 10 December 1824) was an American lawyer and attorney general of Maryland in 1806.

Admitted to the Maryland bar, he attained high rank, but twice declined the office of United States Attorney General when it was offered by Presidents Thomas Jefferson and James Madison. Mason ran for one of Maryland's seats in the United States Senate in 1816, but lost.

Relations John Thomson Mason was a nephew of George Mason (1725–1792); son of Thomson Mason (1733–1785); brother of Stevens Thomson Mason (1760–1803); half-brother of William Temple Thomson Mason (1782–1862); first cousin of George Mason V (1753–1796); first cousin once removed of Thomson Francis Mason (1785–1838), George Mason VI (1786–1834), Richard Barnes Mason (1797–1850), and James Murray Mason (1798–1871); uncle of Armistead Thomson Mason (1787–1819) and John Thomson Mason (1787–1850); father of John Thomson Mason Jr. (1815–1873); and great uncle of Stevens Thomson Mason (1811–1843).