Asplenium montanum, commonly known as the mountain spleenwort, is a small fern endemic to the eastern United States. It is found primarily in the Appalachian Mountains from Vermont to Alabama, with a few isolated populations in the Ozarks and in the Ohio Valley. First described in 1810, it grows in small crevices in sandstone cliffs with highly acid soil. It can be recognized by its dark blue-green, highly divided leaves. Asplenium montanum is the ancestor, through hybridization, of several other ferns of similar habitat.