Fern Cave NWR was purchased in 1981 to provide protection for the federally endangered gray and Indiana bats. It consists of 199 acres of forested hillside underlain by a massive cave with many stalactite and stalagmite-filled rooms. The cave has five hidden entrances with four occurring on the Refuge. Fern Cave contains the largest wintering colony of gray bats in the United States with over one million bats hibernating there in the winter. Bat experts also think that as many as one million Indiana bats may be using the cave and an expedition into the cave is being planned for the future.

A majority of the Refuge is on the western slope of Nat Mountain, located between Scottsboro and Huntsville, Alabama. The eastern-most section starts at about 1500 feet in elevation and the northwestern edge borders the Paint Rock River, a tributary of the Tennessee River, at about 590 feet. The higher elevations are dominated by hickory-oak-pine forest with bottomland hardwoods such as oak, basswood, maple and beech along the lower, wetter areas.

Although this refuge is only 199 acres in size, there is a diverse variety of species that make their home here. Two hundred species of birds, mammals, fish, reptiles, and amphibians use the refuge. A unique array of cave fauna in addition to the endangered bats abound. One survey expedition by a biologist and geologist documented cave fish (Typhlichthys subterraneous), cave crayfish (one female with eggs), surface crayfish, banded sculpins (Cottus carolinae), bluegill (Lepomis macrochirus), yellow bullhead catfish (Ictalurus natalis), cave salamanders (Eurycea lucifuga), northern slimy salamanders (Plethodon glutinosus), honey-colored crickets (Orthoptera: Euhadonecus), mosquitoes (Diptera: Culicidae), crane flies (Tipulidae), heliomyzid flies (Diptera: Heliomyzidae), frogs (Anura), and white millipedes (Diplopoda). Above ground, white-tailed deer, turkeys, migratory songbirds, squirrels, opossums, raccoons, and rabbits abound.

Early spelunkers (cave explorers) started exploring Fern Cave in the 1960's and have described the cave system as a vertical and horizontal maze with over 12 separate levels and interconnected by numerous pits and canyons. The horizontal section of the cave is known to be over 15 miles long and vertical drops of up to 450 feet are found within. These features have contributed to it being described as the most spectacular cave in the United States and have given it fame both nationally and internationally.

A limited amount of research has been done in the cave over the past couple of decades due to the inaccessibility of the cave. Entrance to the cave is difficult and at least one experienced caver has died entering this cave. Historically, the cave has served as a winter home to the largest colony of gray bats in the United States. Over one million of these federally endangered gray bats hibernate in the cave each year and it is estimated that as many as one million Indiana bats, another endangered species, may be using the cave.

Fern Cave NWR gets it's name from the federally endangered American Hart's-tongue fern. Over the past twenty years, the number of plants has dwindled from twenty to just a couple as the result of unscrupulous plant collectors. We can only hope that through increased education and enforcement efforts, this unique species will continue to be found on the refuge.