Stephen van Rensselaer III (November 1, 1764 – January 26, 1839) was Lieutenant Governor of New York and a member of the United States House of Representatives, as well as a soldier, businessman and landowner. The heir to one of the largest estates in New York, his holdings made him the tenth richest American of all time, based on the ratio of his fortune to contemporary GDP. He founded the institution which became Rensselaer Polytechnic Institute.