The MacGillycuddy () were a sept, or branch, of the O'Sullivan Moore clan. The MacGillycuddy is recorded as being one of a smaller number of Gaelic chieftains whose lands were returned post the Cromwellian confiscations, which explains why the name survives to this day. The MacGillycuddy family tomb is at Kilgobnet (Kerry), between the mountains and Killorglin. The clan chief, McGillycuddy of the Reeks, owned land in this part of Munster until the end of the 20th century. The word "reek" is a Hiberno-English version of the English word "rick", meaning a stack.