Thomas Mifflin, an American revolutionary general, born in Philadelphia in 1744, died in Lancaster, Pa., Jan. 20, 1800. He was by birth and education a Quaker, entered public life in 1772 as a representative from Philadelphia in the colonial assembly, and in 1774 was a delegate to the first continental congress. In June, 1775, he accompanied Washington to Cambridge as his first aide-de-camp, with the rank of colonel. Subsequently he was adjutant general, and in the spring of 1776 was commissioned as a brigadier general. He distinguished himself in the battle of Long Island, and in the latter part of 1776 raised considerable reinforcements in Pennsylvania for Washington's army. In 1777 he was made a major general, and became an active member of the " Conway cabal." The project of making Gates commander-in-chief failing, he resigned his commission, and in 1783 was elected to congress, of which he became president at the close of the year. In 1785 he was speaker of the Pennsylvania legislature, and in 1787 a member of the convention which framed the federal constitution.

In October, 1788, he succeeded Franklin as president of the supreme executive council of Pennsylvania; and in 1790 he was chosen governor of Pennsylvania, which office he held till shortly before his death.