Winthrop Sargent (1753 –1820) was Federalist politician, army officer, surveyor, first secretary of the Northwest Territory, and governor of the Mississippi Territory. His papers consist of personal, business, and official correspondence; diaries; business documents; and other papers relating to the St. Clair expedition of which Sargent was adjutant general; to Sargent's survey of the 5th range, Northwest Territory; Sargent's plantations near Natchez; the Congressional investigation of Sargent's administration of the Mississippi Territory and his dismissal; the Ohio Company; the early settlement and administration of the Northwest Territory; and relations with the Spanish governments of Louisiana and West Florida.