The Harps, who were either cousins or brothers, reports differ, were America's first known serial killers. William/Micajah "Big" Harp was born about 1768 and Joshua/Wiley "Little" Harp was born about 1770. They were natives of North Carolina. They killed infants, including their own, children, women and numerous men. They killed for the sake of killing.
They went on a killing rampage in Kentucky and Tennessee in 1797-1799. CrimeMagazine.com tells part of their wicked story:
Big Harp confessed before dying in 1798 to 20 murders, probably not counting the babies. Estimates are as high as 40, but usually around 30. After two killings, one in Knox County and one on the Wilderness Trail, the Harps left Tennessee in December 1798 for Kentucky, where they killed two traveling men from Maryland...
The final stretch of slaughter took place soon after this, in July 1798, when the Harps returned to Eastern Tennessee. The victims included a farmer named Bradbury; a man named Hardin; a boy named Coffey; William Ballard, who was cut open, filled with stones, and dumped in the Holston River; James Brassel, with his throat ripped apart on Brassel’s Knob; John Tully, father of eight. On the Marrowbone Creek in south central Kentucky, John Graves and his teenaged son, out planting crops, had their heads axed. Moving toward Logan County, the Harps came upon a little girl, whom they killed, as they did a young slave on his way to the mill. Once in Logan County, near today’s Adairville, near the Whippoorwill River, they butchered an entire migrating family asleep in their camp, but for one son who survived...
The Harps liked to gut their victims and fill the stomach cavities with rocks to weight them down so they'd sink in a river.
When the authorities caught and killed Big Harp they cut off his head, took it to a crossroads, and attached to an oak tree. The road in Webster County, Kentucky, along which Big Harp’s head was displayed in 1799, was named Harp’s Head Road. The crossing itself is called Harp’s Head.
America’s First Known Serial Killers: The Harps, Big and Little [CrimeMagazine.com]
The Story of the Harp Brothers [Hopkins/Webster County Historical Society]
Serial killers biography: the Harps Brothers: America's first