James Wilkinson, (born 1757, Calvert county, Maryland [U.S.]—died December 28, 1825, Mexico City, Mexico), American soldier and adventurer, a double agent whose role in the Aaron Burr conspiracy still divides historians.
Wilkinson served in the American Revolution (1775–83) as adjutant general under General Horatio Gates (1777–78). In 1784 he settled in Kentucky, where he was active in the movement for independent statehood. In 1787 he took an oath of allegiance to Spain and began intrigues to bring the western settlements of Kentucky under the influence of the Louisiana authorities. Until 1800 he received a Spanish pension and was officially known as “Number Thirteen.” At the same time, however, Wilkinson worked against the Spaniards. In October 1791 he was given a lieutenant colonel’s commission in the U.S. Army, and after the U.S. purchase of Louisiana he became governor of that portion of the territory above the 33rd parallel.
In his double capacity as governor of the territory and commanding officer of the army, Wilkinson attempted to realize his ambition to conquer the Mexican provinces of Spain and perhaps set up an independent government. In an agreement with Aaron Burr, he sent Zebulon M. Pike in 1806 to explore the most favourable route for the conquest of the Southwest. Wilkinson, however, betrayed Burr’s plan to President Thomas Jefferson, reached an agreement with the Spaniards to neutralize the Texas frontier, placed New Orleans under martial law, and apprehended Burr. In the ensuing trial (for treason) at Richmond, Virginia, Burr was found not guilty. Wilkinson himself was under suspicion and subjected to a series of courts-martial and congressional investigations. Nevertheless, he succeeded so well in hiding traces of his duplicity that in 1812 he resumed his command at New Orleans and in 1813 was promoted to the rank of major general. Later in the same year, by making a fiasco of the campaign against Montreal during the War of 1812, he finally brought his military career to a dishonourable end. He obtained a Texas land grant shortly before he died in Mexico City.