Bradley County, AR
The earliest well-documented travelers to enter Bradley County were members of the Dunbar and Hunter expedition, who traveled up and down the Ouachita River in 1804. While the land that would become Bradley County was within the boundaries of the million acres defined as the Quapaw reservation in an 1818 treaty, they were no longer living in that area by the time of the treaty. They ceded the land to the United States government in another treaty in 1824.
Captain Hugh Bradley, a native of Tennessee and a veteran of the War of 1812, led an expedition to explore the Arkansas Territory via the Red River. By 1821 or 1822, this expedition had settled in present-day Lafayette County but in 1825 removed to an area that would become Bradley County. The county was named for Hugh Bradley when it was created out of Union County on December 18, 1840.
Sources: The Encyclopedia of Arkansas History & Culture
Modern Day Adjacent Counties
Bradley County is bordered by Cleveland