There are parts of this story that are probably not true. I will try to point to the most doubtful areas, but this one has become the stuff of legend.
Wiley Harp made his name by being one of two "Harp Brothers" (they were cousins) who are generally credited with being the first serial killers in America. By serial killer we mean someone that has murdered a number of individuals, not all at the same time and not always for a generally accepted cause. Most sources generally agree that the "brothers" deserved their serial killer title and that they grew up together in Orange County, NC.
The parents had moved to America from Scotland and changed the spelling of the original "Harpe". The two Harps, Micajah and Wiley were known to most as Big and Little Harp with Wiley Harp being the smaller of the two. They left home in 1775 together to become overseers of slaves in Virginia. They never made it that far due to the American Revolution. The Harps basically sided with the British as much as any two like themselves ever side with anyone. Their contribution to the war was to burn farmhouses, rape women and pillage whatever they could from each farm they attacked. During one of these raids Little Harp was wounded by the bullet of a local minute man, but survived.
The Harps joined the British regulars in 1780 and fought under Tarleton at King's Mountain, Cowpens and Blackstocks. After that they left the British army, joined up with some Cherokee friends and began to raid small towns in North Carolina and Tennessee. During one trip to North Carolina they kidnapped two wives for themselves, Maria Davidson and Susan Wood. They hustled the women off to the area that is modern-day Chattanooga. Along the way their treatment of the women was so harsh that even another gang member protested their treatment. The Harps killed him of course.
The Harps spent over ten years living among the indians at Nickjack. The British funded many "Indian raids" in which the Harps would participate. They were tipped off one night before the Nickjack community was annihilated and thus escaped along with their wives.
Up to this point the Harp wives had each given birth twice. In every instance the baby was murdered by his father. In 1797 Little Harp, aka Wiley, was legitimately married to one Sally Rice the daughter of a local minister. He kept his former wife as well.
The whole crew left Tennessee for Kentucky after murdering to more people, then killed two more in Kentucky, generally eviscerating their victims and loading their abdomens with stones to sink them in a river or creek. The whole crew was arrested for the further murder of John Langford outside of Crab Orchard, Kentucky. The men escaped, but the women were imprisoned at least long enough for each to give birth. Upon release they immediately sought out their husbands.
After this the Kentucky Governor, James Garrard became involved, initially ordering out a posse. After this posse found, but did not capture the Harps they caught the attention of Henry Scaggs and Colonel Daniel Trabue by murdering Trabue's 13 year old son in order to steal flour. At this point the Kentucky Governor added a $300 reward for the capture of the Harps.
As the Harps moved north to evade an approaching posse they killed four more men. They took refuge in a limestone opening above the Ohio River where it junctions with the Saline. This was also a hideaway for Samuel Mason a famous riverboat pirate of the time who will reappear in our story shortly. During this short stretch of time Wiley Harp murdered his third child in a manner I will not describe.
After resting there the Harps returned to East Tennessee in a killing spree unlike all that had gone before. There are documented murders of 15 people in late 1798. Traveling west to avoid the posse the Harps killed at least six more innocent victims. They were preparing to also kill a local settler named George Smith when the posse rode in on them. The posse wounded and captured Micajah "Big" Harp who would later die from his injuries. Wiley "Little Harp" escaped. Before he died Big Harp confessed to 20 murders. It is usually considered that he killed about 30 including the infants. Big Harp's head was hung on a pole as a warning to passers-by.
Wiley Harp meanwhile had navigated down toward the area of present day Memphis. There he joined in with the riverboat pirate Charles Mason. This is where the story begins to unravel. The most popular ending to our tale is that Wiley Harp, having learned of a reward on the head of the pirate Mason, murdered the pirate and took his head to the authorities in New Orleans. Mason's wife, who had recently escaped the man was said to have identified him positively. Far from receiving the reward Wiley Harp was recognized, arrested, tried and put to death.
Of course nothing can be that easy... There are sharply conflicting reports. One report is that Mason's wife defiantly demanded that the severed head was not that of her husband. It is also frequently reported that two men, neither being Wiley Harp turned the severed head over to authorities.... So, there we have it... either Wiley Harp was hung in New Orleans or he escaped to Kentucky and was never heard from again. Considering how often Harp was "heard from" I suspect he died in New Orleans.