The Moorehead Circle is a woodhenge at the Fort Ancient Earthworks (Ohio, USA): a monumental hilltop enclosure built by the Hopewell culture 2,000 years ago. Now, thanks to Robert Riordan and his team of students and volunteers, a general picture of this amazingly complicated site is coming into focus.
     The Moorehead Circle was a triple ring of large, wooden posts surrounding a central pit filled with red earth. A 40 by 50 ft rectangular structure was located adjacent to this central altar. An arc of alternating trenches and prepared floors on the southern half of the circle may have been something like bleachers, though Riordan doesn't think it necessarily had wooden seats.
     In a presentation of his research at the Eastern States Archaeological Federation's and the Ohio Archaeological Council's joint meeting in Perrysburg in October, Riordan focused on the culmination of the active ceremonial life of the Moorehead Circle. He said that the Hopewell people did not just abandon this remarkable 'ceremonial machine' letting it fall slowly into ruin. Instead, they carefully dismantled its components and then sealed the site beneath a layer of gravel - but not with an earthen mound.
     Typically, the people of the Hopewell culture would have covered a place of such intense ritual activity beneath a mound. The fact that they did not do so here is one of the mysteries of the Moorehead Circle and one reason why it was not discovered prior to 2005. This suggests that there likely are more sites like the Moorehead Circle out there waiting to be discovered.
     The Fort Ancient Earthworks is a part of the Hopewell Ceremonial Earthworks, which is on the United States' Tentative List for eventual consideration for nomination to the World Heritage List.

Edited from Ohio Archaeology Blog (23 December 2012)