In 'The Hills Beyond' T. Wolfe, a native of Asheville, suggest that in many mountain counties of the Appalachia people had not owned slaves and that blacks were unknown before the civil war.
Is the above a confirmed demographic assumption?
The answer to the current question in the title, "Did people in antebellum Asheville N.C. own slaves?" would seem to be a clear yes.
This is actually a remarkably topical question since Buncombe County (of which Asheville is the county seat) "has apparently become the first county in the country to digitize its original slave records" and put them online.
Reportedly the 1850 census recorded 1717 slaves in Asheville, representing about 13% of the population. Whilst this is a non-trivial number it is a much lower proportion than the 33.4% recorded in North Carolina as a whole 10 years later, and lesser still than the numbers found in the states of the Deep South which with the exception of Texas were over 40% slave.
The big difference seems to be that the mountains did not support the big labour intensive plantations which were the classic users of mass slave labour.
According to this link, http://en.wikipedia.org/wiki/History_of_North_Carolina, soemthing like one-third of the pre war population in North Carolina consisted of African slaves. But they were concentrated in the eastern, lowland, part of the state, where cash crops such as cotton, tobacco, and indigo were grown. Slaves and African Americans generally, were "scarce" in the hilly western part of the state, where the economy was based on food crops. Asheville is "deepest" in the hills in this regard, given its location near the western border with Kentucky and Tennessee.
This disinction between "Tidewater" and "Piedmont (foothills) held not only in North Carolina, but also in Maryland, and the former Virginia, which split into West Virgnia and Virginia proper during the Civil War. For instance, in West Virgnia, only 3% of the population is African-American versus 20% in Virginia. And most of West Virginia's 3% is concentrated in the cities, which is to say that the proportion in rural areas is even less than 3%. In mountainous Idaho, the African-American population is about 1%.
Asheville, being a town, would have a high proportion of the slaves in western North Carolina, who would have been engaged in urban "artisan" pursuits. But a strong case can be made that there were very few slaves in the rural areas around Asheville.
I went and downloaded the 1860 Census data on total number of slaves from NHGIS. Note that the 1860 census data was gathered just before the Civil War broke out, and was not compiled and published until after the war had started.
It turns out that Asheville's county (Buncombe) reported 1,933 slaves for that year. This is a bit on the low side for North Carolina. Watuga had the least with 104, Granville had the most with 11,086. Typical numbers seem to be in the thousands, with the Western counties clearly having the least, and the counties in the Eastern half having the most.
However 2,000 people enslaved is still a lot, and some eastern counties had little more than Buncombe (Columbus had only 2,463). So if they are trying to claim some kind of unusual regional purity, I'm not sure the numbers entirely bear that out.
Interestingly, there is also some Census data for that county available from the State of North Carolina, but not for that county past 1850.