Earthworks | History | The Ohio River Scenic Byways Visitor Center
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The Earthworks

The Earthworks (100 BCE – AD 500)

When the pioneers arrived there were mysterious earthworks spread out over the area. Today four sites are the surviving remnants of what we now identify as the Adena Mound and the Hopewell ceremonial center that are located in what is now present day Marietta. These four remaining sites were given European Latin names by the pioneers.


Conus mound is a large burial mound 30 feet in height and 115 at the base surrounded by an embankment and ditch (like moat). It is located in Mound Cemetery at 5th and Scammel Streets.



This is the largest of the platform mounds. It has four graded ramps and was part of a larger enclosure that included the Capitolium platform mound and Sacra Via. We know about this enclosure because of the drawings made by the early settlers of the area. It is located at 4th and Warren Street. During the Civil War it was an encampment for Union soldiers named Camp Tupper.



Capitolium, the name of the mound on which the library sits, is a platform  mound, 8 feet high by 50 feet long and 20 feet wide. The mound had three ramps up to the surface.   Capitolium was part of the earthworks systems including Quadranaou and Sacra Via. The Washington County Library is an Andrew Carnegie Library completed in 1918.

Sacra Via

Sacra Via

The Sacra Via is a graded way that begins on Third Street and is approximately 680 feet (210 m) long by 150 feet (46 m) wide and ends at or near the Muskingum River. The photo is of the winter solstice sunset alignment along Sacra Via.

Rufus Putnam Drawing of Quadranaou, Capitolium and Sacra Via

A number of the early pioneers wrote journals about their experience of the pioneer life. Rufus Putnam as the superintendent of the Ohio Company kept careful notes on his activities. In his paper “The Plan” he writes about both the plan for the city of Marietta and the earthworks they encountered.

He gave the earthworks the names they have today and was concerned even then on how to preserve them and keep them safe. Rufus Putnam’s papers are preserved in the Marietta College Library, special collections which are available online. Here are two drawings he made of the two sites.

Conus Drawing
Rufus Putnam Drawing of Conus
For more information:
Ephraim George Squier and Edwin H. Davis: Ancient Monuments of the Mississippi Valley (“Smithsonian Contributions to Knowledge”, vol. 1, 1848)

Tours & Programs

Campus Martius Museum

601 Second Street, Marietta, Ohio 45750


The Castle Historic House Museum

418 Fourth Street, Marietta, Ohio 45750


Hidden Marietta Tour Co.


Trolley Tours

127 Ohio Street, Marietta, Ohio 45750


Marietta College Legacy Library: Special Collections

The Library preserves rare books, manuscripts, photographs, paintings, and the Marietta College Archives. Students, faculty, visiting scholars, genealogists, and community members are welcome to use the collections in the reading room during posted hours. Plan ahead for your research visit, please e-mail or telephone to let us know of your interests. Staff will locate material in the collections and have it available upon your arrival. For appointments call 740.376.4545 or email Special Collections ( The Digital Collection is available at