"The position was judiciously chosen, as it commanded not only the mouth of the Muskingum, but swept the waters of the Ohio, from a curve in the river for a considerable distance both above and below the fort.

Important is the station ye fill in every respect, and not least in this, that you seem reserved to exhibit to mankind a specimen of that military splendor, which ornamented the arms of America, and would do honor to the troops of any potentate on earth.

The exact location of the fort cannot be determined as the Ohio River has been widened by damming, and is believed to be underwater near the mouth of the Muskingum.

The Campus Martius fortification of the Marietta settlement was built on the east side of the Muskingum and upriver from Fort Harmar during 1788, and fully completed in 1791 at the start of the Northwest Indian War.

The Picketed Point fortification of Marietta was built in 1791 directly across the Muskingum from Fort Harmar, on the east side of the river's mouth.