PINCKNEY, THOMAS (1750–1828), American statesman and diplomat, was born in Charleston, South Carolina, on the 23rd of October 1750, a younger brother of Charles Cotesworth Pinckney (q.v.). Educated in England, he returned to Charleston in 1773, and was admitted to the bar in 1774. During the War of Independence his early training at the French military college at Caen enabled him to render effective service to General Benjamin Lincoln in 1778–1779, to Count d’Estaing (1779), to General Lincoln in the defence of Charleston and afterwards to General Horatio Gates. In the battle of Camden he was badly wounded and captured, remaining a prisoner for more than a year. Subsequently he was governor of South Carolina in 1787–1789; presided over the state convention which ratified the Federal constitution in 1788; was a member of the state legislature in 1791; and was United States minister to Great Britain in 1792–1796. During part of this time (1794–1795) he was also envoy extraordinary to Spain, and in this capacity negotiated (1795) the important Treaty of San Lorenzo el Real; by that treaty the boundary between the United States and East and West Florida and between the United States and “Louisiana ” was settled (Spain relinquishing all claims east of the Mississippi above 31° N. lat), and the United States secured the freedom of navigation of the Mississippi to its mouth with the right of deposit at New Orleans for three years, after which the United States was to have the same right either at New Orleans or at some other place on the Mississippi to be designated by Spain. In 1796 Pinckney was the Federalist candidate for vice-president, and in 1797–1801 he was a Federalist representative in Congress. During the War of 1812 he was a major-general. In 1825 he succeeded his brother as president-general of the Society of the Cincinnati He died in Charleston on the 2nd of November 1828 Pinckney, like many other South Carolina revolutionary leaders, was of aristocratic birth and politics, closely connected with England by ties of blood, education and business relations. This renders the more remarkable their attitude in the War of Independence, for which they made great sacrifices. Men of Pinckney’s type were not in sympathy with the progressive democratic spirit of America, and they began to withdraw from politics after about 1800.
Sec C. C. Pinckney, Life of General Thomas Pinckney (Boston, 1895).