Cincinnati, Society of the, the oldest military society in the United States. It was founded in 1783 at the close of the Revolutionary War by officers of the Continental Army. It was named after the Roman consul Lucius Quinctius Cincinnatus, who left his plow to defend the republic, and then, after victory, returned to his farm.

The society was organized to preserve the principles for which the colonies had fought; to encourage a spirit of union among the states; and to maintain friendships formed during the war. There are 14 chapters—one in each of the 13 original states and one in France. Membership is limited to male descendants of officers who served honorably for three years or more. There are about 3,200 members.

The society, organized at the suggestion of Major General Henry Knox, met for the first time in Philadelphia in 1784. George Washington was its first president. Headquarters are in Anderson House, a museum of Revolutionary War memorabilia that it maintains in Washington, D.C.