Long's Expedition of 1820

The Stephen H. Long Expedition of 1820 traversed America's Great Plains and up to the foothills of the Rocky Mountains.^[1] It was the first scientific party hired by the United States government to explore the West. Lewis and Clark (1803–1806) and Zebulon Pike (1805–1807) explored the western frontier but they were primarily military expeditions.^[2] A group of scientists traveled to St. Louis (present Missouri) and on to Council Bluff (Nebraska) for the Yellowstone expedition of the upper Missouri River that would have established a number of military posts. The expensive effort was cancelled following a financial crash, steamboat failures, operational scandals, and negotiation of the Adams–Onís Treaty of 1819, which changed the border between New Spain and the United States. The scientists were reassigned to an expedition led by Stephen Harriman Long. From June 6 to September 13, 1820, Long and fellow scientists traveled across the Great Plains beginning at the Missouri River near present Omaha, Nebraska, along the Platte River to the Front Range, and east along the Arkansas and Canadian Rivers of Colorado and Oklahoma. The expedition terminated at Fort Smith in Arkansas. They recorded many new species of plants, insects, and animals. Long called the land the Great American Desert.