Arkansas (/ˈɑrkənsɔː/ AR-kən-saw) is a state located in the Southern region of the United States. Its name is of Siouan derivation, denoting the Quapaw Indians. The state's diverse geography ranges from the mountainous regions of the Ozark and the Ouachita Mountains, which make up the U.S. Interior Highlands, to the densely forested land in the south known as the Arkansas Timberlands, to the eastern lowlands along the Mississippi River and the Arkansas Delta.