In 1819 , the Adams – Onís Treaty set the Arkansas as part of the frontier between the United States and Spanish Mexico . This continued until the United States annexed Texas after the Mexican – American War , in 1846 . The treaty was made shortly after " Old Settler " Cherokees moved to near what became known as Webbers Falls on the Arkansas River . That area , then part of Arkansas Territory would become Indian Territory and later Oklahoma , was traditional territory of the Osage , leading to conflict and a treaty in 1828 but still unresolved by the time thousands of additional Cherokee refugees moved to the area during the Trail of Tears
Trail of Tears
Trail of Tears
Arkansas River