MacCuillinn or Mac Cuillann is an Irish surname. The name is the patronymic form of a personal name derived from cuileann (translation from Irish Gaelic: holly). The name has become Anglicised as MacCullen & McCullen, and MacQuillan & McQuillan. The name appears in Irish mythology. The family are thought to have been Celtic Kings between the 5th and 12th century.
References
Mac Cuilinn Wikipedia(Text) CC BY-SA