Mohnia carolinensis is a species of sea snail, a marine gastropod mollusk in the family Buccinidae, the true whelks.

The sculpture consists of about twelve rather prominent, stout longitudinal ribs, wliicli run nearly straight across the whorls.

These are separated by interspaces of about the same width, in the middle of which there is a much smaller, thin revolving cingulus, alternating pretty regularly with the larger ones around the periphery.

The whole surface is also covered, in perfect specimens, with fine, slightly elevated, wavy lines of growth, which are most conspicuous on the intervals between the ribs.

The aperture is elongated, ovate-fusiform; The outer lip is thin, sharp and regularly curved.