<em>Leavenworthia uniflora</em> (Michx.) Britton (Cruciferae) has the widest geographical range of any of the 11 taxa in the genus, and it is the only one that is not considered threatened or endangered. In southeastern United States, <em>L. uniflora</em> is restricted to cedar glades and other limestone barrens. Populations are infrequent, small in size, and in number of individuals. In Kentucky the species has been collected in seven counties, but some of the collections are very old. Extant populations presently are known to occur on cedar glades in Logan, Simpson and Warren Cos. The geographical distribution pattern qualifies <em>L. uniflora</em> as a rare species in Kentucky, and probably throughout its range. We propose that <em>L. uniflora</em> be added to the list of rare and endangered vascular plant species in those southeastern states in which it occurs.