The United States Army built Fort Harmar after the American Revolution. In 1784, the Congress created by the Articles of Confederation dispatched Colonel Josiah Harmar to the Ohio frontier to discourage illegal settlers or "squatters" from moving into Ohio. Harmar faced great difficulty in carrying out his orders due to a lack of supplies and money to pay his men. Monetary issues plagued the government established by the Articles of Confederation throughout its brief existence.
In October 1785, Harmar ordered the construction of Fort Harmar near present-day Marietta. The stockade was located at the junction of the Ohio River and the Muskingum River. Rather than discouraging squatters, the fort encouraged illegal settlement as the migrants believed Harmar's troops would protect them from American Indian attacks. Due to the small number of soldiers at his disposal, Harmar could not guarantee the settlers' safety. Most early settlements, like the Marietta, were built near the fort, so settlers could flee to the stockade for safety if American Indian forces attacked.
- Harmar, Josiah. The Proceedings of a Court of Enquiry, Held at the Special Request of Brigadier General Josiah Harmar, to Investigate His Conduct, as Commanding Officer of the Expedition Against the Miami Indians, 1790: the Same Having Been Transmitted by Major General St. Clair, to the Secretary of the United States, for the Department of War. Philadelphia, PA: John Fenno, 1791.
- Hurt, R. Douglas. The Ohio Frontier: Crucible of the Old Northwest, 1720-1830. Bloomington, IN: Indiana University Press, 1996.