In Washington County, Virginia, a swamp containing Thuja occidentalis L., and several rare vascular species has been found. Species rare for Virginia include: Rhynchospora capillacea Torrey, Juncus inflexus L. and Juncus articulatus L., Parnassia grandifolia DC., Desmodium canadense (L.) DC., and Solidago patula Willd. There are seven widely disjunct species, five reported new for southwestern Virginia. New to southwestern Virginia are Cypripedium reginae Walter, Rhamnus alnifolia L’Heritier, Pogonia ophioglossoides (L.) Ker., Erianthus giganteus (Walter) Muhl., and Carex howei Mack. The other disjunct species are Carex retroflexa Willd. and (Jalopogon tuberosus (L.) BSP. Physiography and floristics of the site are discussed.