Oliver Ellsworth, American lawyer and politician, 3rd Chief Justice of the United States (d. 1807)
Oliver Ellsworth (April 29, 1745 – November 26, 1807) was an American lawyer, judge, politician, and diplomat. He was a framer of the United States Constitution, a United States Senator from Connecticut, and the third chief justice of the United States. Additionally, Ellsworth received 11 electoral votes in the 1796 presidential election.

Born in Windsor, Connecticut, Ellsworth attended the College of New Jersey where he helped found the American Whig–Cliosophic Society. In 1777, he became the state attorney for Hartford County, Connecticut and was selected as a delegate to the Continental Congress, serving during the remainder of the American Revolutionary War. He served as a state judge during the 1780s and was selected as a delegate to the 1787 Philadelphia Convention, which produced the United States Constitution. While at the convention, Ellsworth played a role in fashioning the Connecticut Compromise between the more populous states and the less populous states. He also served on the Committee of Detail, which prepared the first draft of the Constitution, but he left the convention before signing the document.

His influence helped ensure that Connecticut ratified the Constitution, and he was elected as one of Connecticut's inaugural pair of Senators, serving from 1789 to 1796. He was the chief author of the Judiciary Act of 1789, which shaped the federal judiciary of the United States and established the Supreme Court's power to overturn state supreme court decisions that were contrary to the United States Constitution. Ellsworth served as a key Senate ally to Alexander Hamilton and aligned with the Federalist Party. He led the Senate passage of Hamiltonian proposals such as the Funding Act of 1790 and the Bank Bill of 1791. He also advocated in favor of the United States Bill of Rights and the Jay Treaty.

In 1796, after the Senate rejected the nomination of John Rutledge to serve as Chief Justice, President George Washington nominated Ellsworth to the position. Ellsworth was unanimously confirmed by the Senate, and served until 1800, when he resigned due to poor health. Few cases came before the Ellsworth Court, and he is chiefly remembered for his discouragement of the previous practice of seriatim opinion writing. He simultaneously served as an envoy to France from 1799 to 1800, signing the Convention of 1800 to settle the hostilities of the Quasi-War. He was succeeded as chief justice by John Marshall. He subsequently served on the Connecticut Governor's Council until his death in 1807.