Fort McKinley is an unincorporated community and census designated place in Harrison Township in Montgomery County, Ohio, United States. It was delineated as a census-designated place at the 2000 census, when its population was 3,989. It was not delineated as a CDP for the 2010 census. Fort McKinley is part of the Dayton Metropolitan Statistical Area. Fort McKinley was platted in 1914.