Original contributions:
- American pioneers to the Northwest Territory - established the first permanent American settlement in the Northwest Territory in 1788, opening the westward expansion of the new United States.
- Mound Cemetery - home to the Great Mound or Conus in Marietta, Ohio, and reportedly home to the largest number of American Revolutionary War officers buried in one location.
- Greene, Griffin (1749-1804) - a commissary, paymaster, and quartermaster to the Continental Army during the American Revolutionary War, a pioneer to the Ohio Country, and a director of the Ohio Company of Associates.
- Hildreth, Samuel (1750–1823) - a surgeon in the Massachusetts militia and aboard Massachusetts naval privateers during the American Revolutionary War, father of Samuel Prescott Hildreth.
- Hildreth, Samuel Prescott (1783–1863) - a pioneer physician, scientist, and historian; his history books provide insight into the early settlement of Marietta, Ohio and the Northwest Territory; son of Samuel Hildreth.
- Saltonstall, Nathaniel (1727-1807) - a Connecticut militiaman and a captain of Connecticut naval privateer ships during the American Revolutionary War.
- Sproat, Ebenezer (1752–1805) - a colonel in the Continental Army during the American Revolutionary War, a pioneer to the Ohio Country, and the first sheriff in the Northwest Territory.
- Stacy, William (1734-1802) - a lieutenant colonel in the Continental Army during the American Revolutionary War, taken prisoner-of-war during the Cherry Valley massacre, and a pioneer to the Ohio Country.
- Tupper, Anselm (1763-1808) - a lieutenant in the Continental Army during the American Revolutionary War, enlisted while only eleven years old, and a pioneer to the Ohio Country.
- Tupper, Benjamin (1738-1792) - a general of the Continental Army during the American Revolutionary War, a co-founder of the Ohio Company of Associates, and a pioneer to the Ohio Country.
- Woodbridge, Benjamin Ruggles (1739-1819) - a colonel in the Massachusetts militia during the American Revolutionary War and a member of the Massachusetts legislature.