Fort Ancient in Ohio

Fort Ancient is one of a series of Hopewell and Adena structures built in North America between roughly 1,000 BC and 400 AD. Lately, some archaeologists have said it might not have been a defensive work, as if people would build an enclosed structure with high banks of earth on a hilltop for fun, or for a vague ceremonial reason. They estimate it took 400 years to build, apparently based on the amount of work involved (553,000 cubic yards of soil, assuming no erosion). However, the original structure was later occupied by a different civilization. They may have not needed it as a fort. Also, the 60 "gateways" could have had other purposes, and could have been wooden gates or sentry stands that have long-since been burned, torn down, or simply decayed and eroded.

Here's an idea of the size of the structure. This postcard is dated somewhere between 1920 and 1950.

The Fort Ancient web site contains some good information.

Here's what the Ohio Historical Society has to say about it:

Fort Ancient is a series of earthen embankments that extend for more than three-and-a-half miles around a high bluff along the Little Miami River in Warren County, Ohio. It was built by the Hopewell culture between 100 B.C. and A.D. 400.

Although it is called a "fort," it probably never served as a defensive work. Ditches are located inside the walls rather than outside as might be expected if it was an actual fort. Also, there are more than 60 gateways in the enclosure, which would have made it difficult to defend against enemies.

Fort Ancient is a National Historic Landmark and is being considered for nomination for inscription on the UNESCO World Heritage List.

The site offers beautiful vistas along hiking trails as well as the remains of the marvelous ancient earthworks. Convenient picnic areas can be found along the road at the site.

More detail here:

What to know about the site:

Fort Ancient includes 18,000 feet of earthen walls within a hundred acre complex. The Hopewell culture (100 B.C. – A.D. 500) built the earthwork using the shoulder blades of deer, split elk antler, clam shell hoes and digging sticks to dig the dirt. They then carried the soil in baskets holding 35 to 40 pounds. Archeologists estimate that Fort Ancient is composed of approximately 553,000 cubic yards of soil and that it took approximately 400 years to complete the structure.

The name, Fort Ancient, is a source of some confusion. First, despite its name, Fort Ancient was constructed by the Hopewell culture nearly 2,000 years ago. People of the much later Fort Ancient culture (A.D.1000 - A.D.1650) built a village and cemetery within the structure, which prompted some of the first archeologists to attribute the earthwork to the Fort Ancient culture.

The site’s name is also confusing because Fort Ancient was likely never used as a defensive fortress as early archeologists first hypothesized. Ditches were constructed inside the walls rather than outside as might be expected in a fortification. In addition, there are more than 60 gateways in the walls, making it difficult to defend the site against enemies. Now archeologists believe Fort Ancient was used as a major ceremonial complex where hundreds of people gathered at specific times of year. “One of the most interesting archaeological components is the evidence of archaeoastronomy,” says Jack K. Blosser, Site Manager at Fort Ancient. Blosser explains: There are four small circular, stone faced mounds approximately 512 feet apart that form a nearly perfect square. By watching the sun and the moon rises that occurred within the “U” shaped games within the walls, the Hopewell people had the ability to have ceremonial and social observances at specific times of the year. It seems that the sun was used for annual events while the moon was used in conjunction with a decadal event.

At Fort Ancient, you can learn about this important earthwork and the people who built it through the site’s museum, prehistoric gardens, and 2.5 miles of hiking and interpretive trails. Convenient picnic areas can be found along the road at the site.