Mullach Glas is a 622-metre mountain in the Maumturk Mountains of Connemara, County Galway, whose Irish name means “grey/green summit” and which has also been recorded as Shannagirah. The fifth-highest peak in the Maumturks, it stands on a southeastern massif with Binn Mhór and Corcogemore, beyond the main spine of the range and separated by the pass of Máméan. That pass has been a pilgrimage site dedicated to Saint Patrick since the 5th century. Mullach Glas is especially known to hillwalkers for its ridge position, its use in longer traverses, and its place on the Maamturks Challenge, an annual crossing organized since 1975.