Riker-Todd was a Middle Woodland Hopewell Mound located on a glaciated upland in Union Township, Butler County, Ohio. Radiocarbon dating and anthropogenic stratigraphy indicate that there were at least three different mound building episodes between ca. 5 B.C. to A.D. 631. Stylistically distinctive artifacts and mtDNA from Riker-Todd Mound fall within the range of other Middle Woodland Hopewell sites in North America and most closely resemble those from Mound 25 of the Hopewell Mound Group, including a large corner-notched, flaked-stone biface manufactured from Knife River flint. Although maize was part of the Hopewell diet, stable carbon obtained from human bone collagen failed to find an isotopic signature.