Watch HDToday. The feud between the Hatfields and McCoys is perhaps the most famous family conflict in American history. As legend has it, two neighboring families in the backwoods of Appalachia waged a crude and bloody war against each other over a stolen hog, an illicit romance, and longstanding grudges. Yet the events that took place near the end of the 19th century between the Hatfields and McCoys are part of a much richer and more complex narrative of the American experience.