|File:Campus Martius map.jpg|
Campus Martius was the name the settlers of Marietta gave to the fortifications they built to protect their new settlement.
Campus Martius was chosen as a reference to the civilization of ancient Rome. Located within the settlement, Campus Martius was intended to provide protection from Native American attacks. Log walls surrounded the outside of the fortifications, and within their confines were four blockhouses. In the early days of the settlement, one of the blockhouses served as the community's school and another as a church. Campus Martius was also the original location for town meetings, the New Englanders' form of local government, and the first court in the region.
The Ohio Historical Society currently operates a museum at Campus Martius. One of the original houses of Campus Martius has been preserved