The MacQuillan Clan is a Scottish family with roots in the historical region of Ulster, particularly in County Antrim. They are known for their connections to the O'Neill dynasty and their role in the medieval period, where they were prominent landowners and warriors. The clan's name is derived from the Gaelic "Mac Cuill," meaning "son of Cuill." Historically, the MacQuillans were involved in various conflicts and alliances, particularly during the Tudor conquest of Ireland. They held the Ballycastle area and were known for their stronghold at Dunluce Castle. Today, the clan's heritage is celebrated by descendants and those interested in Scottish and Irish history.