Cumberland sandwort (Arenaria cumberlandensis) is a small, delicate plant found only in shaded rockhouses on the Cumberland Plateau in northeast Tennessee and southeast Kentucky. The thin basal leaves form small clumps in the fine, loose sand of the rockhouse floors and are visible throughout the winter and spring. From July through August, small white flowers are produced on slender stems growing about 6 inches in height.

This plant is restricted to the Big South Fork of the Cumberland River watershed in Fentress, Morgan, Pickett, and Scott counties in Tennessee and McCreary County, Kentucky.

The plants are very sensitive to damage by trampling that disturbs the shallow root system and compacts the fine, loose sand. As a result of trampling, rarity of the habitat, and the geographic isolation, the U.S. Fish and Wildlife Service listed the Cumberland sandwort as federally endangered on June 23, 1988.