Hundreds of frontier forts helped enable the westward expansion of the United States, and they were built on land that was very much abroad at the time. Fort Harmar, built in 1785 in the Northwest Territory, was the first. Others appeared in today’s Ohio and Indiana, including Forts Deposit, Defiance, Hamilton, Wayne, Washington, and Knox. Each of these bases helped waves of U.S. settlers move into the lands of Native American nations, pushing Indians progressively westward.

David Vine, Base Nation_ How U.S. Milit…, loc. 58