It was home to Rufus Putnam, Benjamin Tupper, Arthur St. Clair, and other pioneers from the Ohio Company of Associates during the Northwest Indian War.

A firsthand description of the fort is provided in Hildreth's Pioneer History, Campus Martius is the most handsome pile of buildings on this side of the Alleghany mountains, and in a few days, it will be the strongest fortification in the territory of the United States.

It stands on the margin of the elevated plain on which are the remains of the ancient works [mounds], mentioned in my letter of May last, thirty feet above the high bank of the Muskingum, twenty-nine perches distant from the river, and two hundred and seventy-six from the Ohio.

Fort Harmar was constructed several years earlier, in 1785, by United States troops on the west side of the mouth of the Muskingum River.

Another group of associates moved about 20 miles up the Muskingum River from Marietta, near the mouth of Wolf Creek; they built Fort Frye for protection during the war at the site of modern-day Beverly, Ohio.