Christopher Greenup (ca. 1750–1818), attorney and public official, was a native of Loudoun County. He studied law before serving during the American Revolution as a first lieutenant in the Continental army, 1777–78. Greenup was later a colonel in the Virginia militia. In 1781 he moved to Frankfort in what was then the Kentucky district of Virginia. Greenup was admitted to the local bar and represented Fayette County in the House of Delegates, 1785–86. He sat in the Kentucky conventions of 1784, 1785, and 1788, where he supported statehood. Greenup was a member of the first congressional delegation from Kentucky, serving in the United States House of Representatives, 1792–97. In 1804 he was elected governor as a Jeffersonian Republican and completed one four-year term. He then resumed his legal career while continuing to be politically active in Frankfort. TJ apparently met Greenup in the 1790s while both men were serving in the federal government at Philadelphia, and they corresponded sporadically on business thereafter (ANB description begins John A. Garraty and Mark C. Carnes, eds., American National Biography, 1999, 24 vols. description ends ; DAB description begins Allen Johnson and Dumas Malone, eds., Dictionary of American Biography, 1928–36, 20 vols. description ends ; PTJ description begins Julian P. Boyd, Charles T. Cullen, John Catanzariti, Barbara B. Oberg, and others, eds., The Papers of Thomas Jefferson, 1950– , 38 vols. description ends , esp. 25:99–100; Heitman, Continental Army description begins Francis B. Heitman, comp., Historical Register of Officers of the Continental Army during the War of the Revolution, April, 1775, to December, 1783, rev. ed., 1914 description ends , 261; Leonard, General Assembly description begins Cynthia Miller Leonard, comp., The General Assembly of Virginia, July 30, 1619–January 11, 1978: A Bicentennial Register of Members, 1978 description ends , 156; Frankfort Argus of Western America, 1 May 1818; Washington Daily National Intelligencer, 16, 20 May 1818).

A missing letter from TJ to Greenup of 30 July 1815 is recorded in SJL.