There is very little that can be unambiguously identifed as "folk" music in my local (Central US) area, but since the question also relates to contests our annual Walnut Valley Association site may have some useful information. The Home Page won't be too interesting, but the link in the sidebar there to Contests Archive may get some useful reference info.

A Summary History indicates:

"The Walnut Valley Association was formed in 1972,with its sole purpose to produce the Walnut Valley National Guitar Flat-Picking Championships Festival...."

The origins aren't really all that precisely known, and you run into people who claim they've been attending since 1968 or so – but that's the "official" history.

The "official history line" continues:

"The contests are a major part of the festival. Along with the National Flat Pick Championships and the National Finger Pick Championships, the Walnut Valley Festival hosts the International Autoharp, National Mountain Dulcimer, National Hammered Dulcimer, National Bluegrass Banjo, Walnut Valley Old Time Fiddle, and Walnut Valley Mandolin Championships. Over the course of years, the contests at Winfield have attracted more than 3,000 contestants from all 50 states as well as many foreign countries including Australia, Canada, Denmark, Sweden, England, Germany, Italy, Japan, New Caledonia, Switzerland, and Wales. Well-known Winfield winners include Mark O'Connor of Nashville, Tennessee, who has won or placed in more Walnut Valley Festival contests than any other contestant. Mark won the National Guitar Flat-Picking Championship in 1975 and 1977, and also won the Walnut Valley Fiddle Championship in 1974 and 1977. Alison Krauss of Nashville, won the Walnut Valley Fiddle Championship in 1984 and Steve Kaufman of Alcoa, Tennessee, is the only three-time winner of the National Guitar Flat-Picking Contest, having won in the years 1978, 1984, and 1986 respectively. (Tennessee has consistently produced the most winners over the years.) Other Winfield winners include Mandolin virtuoso Chris Thile, the Mandolin Champion in 1993 and Dixie Chick fiddler Martie Erwin Seidel in 1987 and 89. "

The fiddle contest is the only one that's listed as "Old Time Fiddle," and I can't say how closely the "old-time" part of it is observed. In the few contest bits I've watched, mostly guitar and mando, most of the selections were "traditional," but quite frankly at my most recent 15 or so years attendance there I've never made it out of the campground to listen to the "organized" stuff.

You'll have to make your own associations to "folk," but the competitors lists may give you an idea of who has been competing in this obscure corner of the Midwest, so that you can select the ones for whom you can make the folk connection. There's also the possibility you may be able to verify a competitive connection for someone you already know as a folkie.

At the Contests Archive page, you'll find links to the lists of winners, usually first three places, for:

National Guitar Flat Pick
Finger Style Guitar
International Autoharp
National Mountain Dulcimer
Walnut Valley Mandolin
Walnut Valley Fiddle
National Hammer Dulcimer
National Bluegrass Banjo

At the bottom of the Contests page there are also links to each of the years from 1972 through 2004, where winners for each year are composited.

Probably of even lesser interest to your research, the sidebar at the home page links to Past Performers. So far as I can guess, this is just another list of "names of players" (393 of them), but one never knows what may be useful for a dissertation.

It may be worth noting that a group from the Mandolin Café usually is present at the WVA festival. They're located "*back east" where all them professional-student-hippy-radicals come down from, so they likely have more "folk connection." I believe a few of them come in here, but a separate query at their site, if you can find a place to post it, might get some input – if you're interested in US folkish competition.

* "back east" is about 150 miles in this case, but they're in a major college town and close to both the state capitol and the "big city" Kansas City KS/MO complex where there seems to be more activity.

The "gawkers gallery" may also be interested in the WVA scheduled performers for 2005. For the "flavor" of the WVA Festival, the "unofficial site" at Picker's Paradise is more revealing than the official place.

John