"But here was old Kentucky..."
I have an old book titled, "The Kentucky Rifle," by Merril Lindsay (1972 edition). It's a book of photographs of 77 fine old original longrifles photographed by a man named Bruce Pendelton. All these highly crafted, beautifully ornate old guns were gathered in one place from all over the United States. Mr. Lindsay in his intro of the book asks the question, "Where did the name come from?" Here's what he wrote:
"Following the American victory at the Battle of New Orleans, substantially won by the Kentucky rifle in the hands of about two thousand frontiersmen from Kentucky, a ballad, "The Hunters of Kentucky," was written. It dramatized the exploits of these undisciplined riflemen who defeated the military might of England. The ballad became widely popular throughout the new nation, so much so that the version sung at the Chatham Garden Theatre in New York City was published in the form of sheet music by George Willig in Pennsylvania German before it had run its course. In the fifth stanza of the lyrics, the Kentucky rifle received its name which was to stay with it from that time on. The expression "Kentucky rifle" became one of those singular examples of a designation documented in its own period."
"But Jackson he was wide awake and wasn't scar'd at trifles
For well he knew what aim we take, with our KENTUCKY RIFLES,
So he led us down to Cypress Swamp, the ground was low and Mucky,
There stood John Bull in martial pomp but here was old Kentucky."
"The frontiersmen who went to Kentucky and on into Louisiana Territory bought and brought their rifles from Pennsylvania, Maryland and Virginia but chiefly from Pennsylvania towns along the roads leading to the West are remembered as the locations of the schools of rifle design. There were few, if any, Kentucky rifles made in Kentucky, although there were some Kentuckys made in Tennessee, Ohio and Indiana..."
So, the name according to the author, Mr. Merril Lindsay.
Also according to Mr. Lindsay, the Lancaster (Pennsylvania) school of gunsmithing was in all probability the original home of the "Kentucky" rifle, and Lancaster gunsmith Jacob Dickert was one of the most well-known makers of the rifles.