The flora of Hardin County comprises 1,126 species, subspecies and varieties in 494 genera and 129 families, representing roughly 40% of Kentucky’s known vascular flora. Of these, 30 are considered rare, threatened, or endangered within Kentucky. About one-third of the flora is extraneous to the lower Ohio Valley and is composed of species with predominantly Appalachian, northern, southern, and Coastal Plain distributions. Twelve species appear to be endemic to or characteristic of the Interior Low Plateaus Province of Kentucky and Tennessee. This floristic diversity is a consequence of geographic location in combination with an edaphically and physiographically diverse environment.