In my last posting under the Louis-Philippe thread (and good to see there is some additional documentation of his visit to Bardstown) I indicated that if bourbon whiskey did not receive its name from Bourbon County, the fact of Bourbon County's existence would have lent a reinforcing aspect to the name. I did not mean this in the sense that the name came from both the County name and another source. Rather, I meant that people could mistake reasonably that the name bourbon came from Bourbon County, for two reasons. First, Limestone, now Maysville on the Ohio River, having once been in that County, was a shipping point for whiskey. Second, the County even as truncated did comprise numerous, respected distillers in its early years. So I haven't said the Bourbon County name has nothing to do with the name of bourbon and this would be true even if a left field theory like Bourbon cane - or Bourbon Street in New Orleans - was the true explanation.
The direct link of the Bourbon princes to American whiskey I mentioned is not a smoking gun of course but I regard it as significant. We are trying to interpret what is most probable from the available evidence. A rather striking anecdote, that Bourbon princes were drinking and travelling with American whiskey in or near its heartland to me provides the best indication so far of how the whiskey acquired its name. The Catholic connections to distilling, and French Royalist influence in Kentucky (and Louisiana) are certainly interesting and indeed, bourbon whiskey and Cognac bear some connections in palate and production style. This is all food for thought but I think the closest connections so far between whiskey and something called Bourbon are the best or most plausible places to look, namely: 1) Bourbon was once made in and sold from an area called Bourbon. 2) Whiskey was once purchased and consumed by visiting figures of the French branch of the House of Bourbon in 1797. Regarding the first connection, whiskey was shipped from Limestone when in Bourbon County, yes. Yet the first evidence of the name bourbon is the 1821 advertisement from the Western Citizen in Bourbon County. The 40-year or so gap seems hard to understand. Plus, why would an advertiser call a local product after the local geographical name, especially in those days when communities were relatively isolated and most consumable, hard-to-ship products were made locally anyway? One explanation might be that bourbon, being aged, was different than common whiskey, but in that case why not call it old whiskey? (A lot of the old ads did so in fact. One in 1826 is cited in the 1992 Kentucky Encyclopedia links I mentioned in another thread). If different types of whiskey were in the market in 1821 in Bourbon County, e.g., some from Monongahela, or Scotland, that might be a reason to call the local product by the County name. But was that the case? Also, whiskey surely was made in many areas outside Old Bourbon that was bourbon-like in style, although not shipped heavily of course from all those places whereas it was from Limestone/Maysville (yes). Elijah Craig is the best example perhaps of an early figure, associated closely with bourbon's development, who never having lived in any iteration of Bourbon County. I believe the same was true of Evan Williams of Louisville.
So we come back again to the two closest connections: the short period when Limestone was in Bourbon County and the anecdote of the travelling Princes drinking American whiskey in the late 1790's, an anecdote given historical significance (albeit partly comic) by an eye-witness to the event. The latter seems to me the more plausible explanation why the name bourbon stuck especially in its areas of production, not just in distant export markets. A trade name in an export market often is different than the local name, e.g., Chester cheese in France is Cheshire cheese in England. True, the Princes' connection has not previously been mentioned in the literature. One would think it would have been noted had it been the true explanation, e.g., by Hoskins in his 1859 book, or by various Kentucky historians. They all would have known of the Royal visit by the Duke of Orleans and his brothers in the 1790's. But maybe they missed it because the name caught on so early in a way not easily traceable and because of the "camouflage" of Bourbon County as proposed earlier.
I think more research, especially in local newspapers (was there one in Limestone, for example?) or merchants' records, between the 1770's and 1821 might point the way to the final answer.