Thomas Hart Benton (3/14/1784 - 4/10/1858) was a U.S. Senator from Missouri and a staunch advocate of westward expansion of the United States. He served in the Senate from 1821 to 1851, becoming the first member of that body to serve five terms. Benton was an architect and champion of westward expansion by the United States, a case that became known as the Manifest Destiny.