What formed the U.S eastern and western boundaries?

Answer 1

The U.S. eastern boundary was primarily established by the Atlantic Ocean, while the western boundary was shaped by a series of treaties, purchases, and conflicts, including the Louisiana Purchase in 1803 and the Oregon Treaty in 1846. The original 13 colonies extended to the Appalachian Mountains, and westward expansion was driven by the idea of Manifest Destiny. The borders were further defined through negotiations with Spain and Mexico, as well as the annexation of Texas and the acquisition of territories following the Mexican-American War.