Ellsworth, Oliver (1745–1807), a United States statesman and jurist. He played an important role in the founding of the republic. Ellsworth was born in Windsor, Connecticut, and graduated from the College of New Jersey (now Princeton University). He practiced law in Hartford and became a leading lawyer. During the Revolutionary War Ellsworth served in the Continental Congress (1777–83).

Ellsworth was a delegate to the Constitutional Convention of 1787, and was one of the sponsors of the Connecticut Compromise, which settled the dispute over representation in Congress. From 1789 to 1796 he was in the United States Senate, where he had great influence in organizing the new government. In 1796 he became the third chief justice of the United States. In 1799 President John Adams sent Ellsworth and two other commissioners to Paris to negotiate a treaty with France. The next year Ellsworth resigned from the Supreme Court because of failing health.