Natchez, in the extreme southwestern corner of the United States, was threatened by Spain in 1800 and later by France and Great Britain, leading President Jefferson in 1801 to decide that a road from Nashville to Natchez was necessary for the safety and welfare of the nation. The route, later known as the Natchez Trace, had earlier linked Natchez with the Choctaw Nation as an Indian trail, was called the “Path to the Choctaw Nation” by the British after they established permanent settlements in the district between 1763 and 1779, was called “Camino de Cumberland a Natches” by Spain after conquering Natchez in 1779 during the American Revolution, and was improved by Americans after 1798 to facilitate direct communication with Nashville. The Old Natchez District, five hundred miles from Nashville, became part of the United States in 1798; Natchez had become a French colony in 1716, and in 1800 the district had 5,361 free people, 3,489 enslaved people, 8,850 people in total, and the town of Natchez had 500 inhabitants, while the United States had a population of 5,308,483. The Trace quickly became an important highway and mail route that made communication between Natchez and Washington, D.C., fairly safe and rapid; troops marched over it in 1803 when war seemed near and again in 1812 at the outbreak of war with Great Britain, swift postriders carried mail between Nashville and Natchez in less than 10 days, and Ohio Valley pioneers floated their products to Natchez or New Orleans in flatboats and returned home afoot or on horseback over the Trace. After 1820 steamboats carried most Natchez traffic, and parts of the Trace were abandoned while other parts were used as local roads. The Natchez Trace Parkway, a unit of the National Park System, preserves features associated with this history, including the worn old trace, Mount Locust, and Emerald Mound, the second largest temple mound in the United States, erected by predecessors of the Natchez Indians between 1300 and 1600 A.D.