A qualitative inventory of the vascular plant species of Mount Jefferson State Natural Area and contiguous areas was conducted from fall 2004–summer 2008. The 368 ha site is the most southeastern peak within the Amphibolite Mountains Macrosite of northwestern North Carolina. The study area is near equidistant from the towns of Jefferson and West Jefferson in central Ashe County, and lies within the Blue Ridge Range of the Southern Section of the Blue Ridge Physiographic Province. Nine major communities were recognized, including a High Elevation Mafic Glade, which is only the second documentation of such a community in North Carolina or globally. Vascular plants consist of 706 specific and infraspecific taxa in 383 genera from 109 families. Plants represented were one Equisetophyta, six Lycopodiophyta, twenty-four Polypodiophyta, five Pinophyta, and 670 Magnoliophyta. The largest families in taxa richness were the Asteraceae (96), Poaceae (82), Rosaceae (37), Cyperaceae (32), Fabaceae (30), and Lamiaceae (25). One-hundred and sixty taxa (22.7%) were exotic. Thirty-four taxa were on the “NC Watch List” and an additional sixteen were regarded as “Significantly Rare” in North Carolina. One hundred and twenty-nine taxa were Ashe County records. Eight taxa were documented for the first time in North Carolina.