These earthworks served as ceremonial centres, built by dispersed, non-hierarchical groups whose way of life was supported by a mix of foraging and farming. Criterion (i): Hopewell Ceremonial Earthworks comprises highly complex masterpieces of landscape architecture. Criterion (iii): Hopewell Ceremonial Earthworks bears exceptional testimony to the unique characteristics of their builders, who lived in small, dispersed, egalitarian groups, between 1 and 400 CE, amongst the river valleys of what is now southern and central Ohio. AuthenticityHopewell Ceremonial Earthworks is authentic to an extraordinary extent, given the long time that has elapsed since its construction, in terms of their locations and settings, forms and designs, materials and substance, and spirit and feeling. High-resolution remote-sensing data for the Seip Earthworks, Hopewell Mound Group, Hopeton Earthworks, and High Bank Works component parts clearly show intact subsurface portions of wall and building constructions.