The Hatfields and McCoys were two families involved in a famous feud in the late 19th century in the Appalachian region of the United States. The conflict began in the aftermath of the American Civil War and escalated over issues such as land disputes, personal grievances, and differing loyalties. The feud gained national attention, particularly after violent confrontations resulted in deaths on both sides. The rivalry became emblematic of family feuds in American culture and has been depicted in various forms of media, including films and television series, highlighting the complexities of loyalty and conflict.