There are a number of theories about the Melungeons, a people who live in Appalachia and number about 50,000. Early European explorers who encountered them regarded them as neither white nor black. Some say the Melungeons are a 'tri-racial' mix of European, Native American, and African people. Other evidence indicates the Melungeons are primarily derived from people of Mediterranean origin. But the Melungeon Heritage Society emphasizes that "'Melungeon' was NOT, is NOT a racial or ethnic group."
According to Wired News article The 'Lost Tribe' of Appalachia, "There seem to be as many stories of how these people came to be as there are Melungeons to tell them: They're from the abandoned colony of Roanoke, they're Portuguese shipwreck descendants, or maybe they're one of the Lost Tribes of Israel." Even the origin of the name 'Melungeon' is up in the air: "It might be a version of the French word for mix: mélange, or from an African word malungo, meaning shipmate, or the Turkish melun jinn, meaning 'cursed soul.'"
Dr A. Zahoor's article, The Melungeons, suggests a possible origin for the word 'Melungeon':
The word 'Melungeon' probably originates from the Arabic ‘Mudajjan’ ... It was originally used as a term of ridicule for the Muslims who made pacts with the Christians and fought their fellow Muslims ... It was also used to describe all the Muslims who remained in the North after first wave of persecution by the Church, and who worked for the Christian nobles on their large country estates. The Turkish term 'Melun-can' which is pronounced identically to Melungeon means "one who has been abandoned."
Nancy Sparks, researcher of Melungeon genealogy, also suggests a Mediterranean origin in her article The Melungeon Connection:
The Melungeons are a people of apparent Mediterranean descent who may have settled in the Appalachian wilderness as early or possibly earlier than 1567. According to Dr. N. Brent Kennedy, the author of 'The Melungeons: The Resurrection of a Proud People', the Melungeons were "a people who almost certainly intermarried with Powhatans, Pamunkeys, Creeks, Catawbas, Yuchis, and Cherokees to form what some have called, perhaps a bit fancifully, 'a new race'."
For the last word, check out the Melungeon FAQ on the Official Website of the Melungeon Heritage Association.