The focal ancestor for this wiki's McCoy line is Michael McCoy, born in 1800 in Lawrence County, Ohio. Michael's parents were John McCoy and Mary Miller. According to both written and oral histories, John McCoy came from Ireland to New Orleans at age 12, but the details of this John McCoy's ancestry are unknown.
The McCoy families in this wiki, descended from John McCoy (b. 1764), are not related to the McCoy families of the infamous Hatfield-McCoy feud. Trust me on this.
The surname McCoy is fairly common in the USA. It may occasionally be spelled as MacCoy, MacCay, McCay, McKay or MacKay in records.
Early immigrants with suname McCoy generally came from Scotland or Northern Ireland. This is consistent with the theory that immigrant John McCoy was born in Donegal County Ireland and was of Scots-Irish1) or Gallowglass2) origin.