Arkansas is a state in the southern region of the United States, home to over 3 million people as of 2017. Its name is of Siouan derivation from the language of the Osage denoting their related kin, 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. Arkansas borders Louisiana to the south, Texas to the southwest, Oklahoma to the west, Missouri to the north, and Tennessee and Mississippi to the east.