Plum Bayou Mounds Archeological State Park in Arkansas preserves the largest known site of the Plum Bayou culture, a Late Woodland mound center occupied from the 7th to the 11th century. Along Mound Lake, it contains 18 mounds, including Arkansas’s tallest surviving prehistoric mounds, within a carefully planned enclosure of embankment, ditch, and lake. People of the surrounding floodplains lived in permanent villages and supported this center, which appears to have been used chiefly by political and religious leaders for ceremonial, social, and political gatherings. Its earthworks, plazas, buildings, feasting evidence, and possible solar alignments make it one of Arkansas’s most important prehistoric sites.