At the time of European settlement in the late 1700s, extensive areas on the Pennyroyal Plain of northwestern Middle Tennessee and southwestern central Kentucky were grass-dominated with scattered and stunted trees and shrubs, apparently as a result of regular burning by Native Americans. These areas were referred to as “barrens” by settlers and because soils were deep and fertile, almost all were in tilth by the middle 1800s. To our knowledge no sites of barrens vegetation from this region, commonly called the “Big Barrens,” escaped cultivation. However, since establishment of the Fort Campbell Military Reservation (FCMR) in 1942, regular burning to maintain open conditions for military training has allowed a “barrens flora” to re-develop on former barrens that had been converted to agriculture. We prepared floristic lists from 22 barrens stands during the growing seasons of 1993, 1994, and part of 1995. The combined list includes 342 species with the Asteraceae (70 species), Poaceae (44), Fabaceae (30), Rosaceae (16), Cyperaceae (15), and Lamiaceae (12) accounting for 55% of the flora. The most frequently encountered taxon and apparent dominant was Schizachyrium scoparium (little bluestem). Community coefficients for all pairwise comparisons averaged >62%, indicating a high degree of similarity between the 22 stands. In addition, 82 species (24%) were constantly present (occurred in >80% of stands). More than two-thirds of the 311 native taxa are intraneous in distribution and the extraneous western (i.e., prairie) element is small (5%). Thirteen taxa are listed as rare elements in Kentucky and/or Tennessee and two of these 13 are federal candidates (C2). Based on historical accounts, many barrens at FCMR represent settlement-era floristic conditions and their preservation is recommended.