The Williamson Mound Archeological District in southwestern Ohio, north of Maud in Butler County, preserves a prehistoric mound on a ridgeline above an intermittent stream that appears to have been built by people of the Hopewell tradition. Although a small hole was dug into its top sometime before 1972, the mound has remained in notably good condition. In an increasingly urbanized part of Butler County, it is one of the region’s best-preserved Hopewell mounds. That strong state of preservation gives it special archaeological importance, recognized by its listing on the National Register of Historic Places in 1975.