The Walnut Valley Association was formed in 1972, with its sole purpose to produce the Walnut Valley National Guitar Flat-Picking Championships Festival, also known as the Flat-Picking Championships, currently known as the "Walnut Valley Festival" or simply "Winfield" to the long time attendees.

Evolving from three days in 1972... to its current five days the 3rd weekend of September annually, it endeavors to produce "family fare" entertainment on four stages simultaneously, a large quality, juried arts and crafts fair, workshops, and acoustic instrument contests. What began with 10 acts and two contests now boasts 30 to 40 acts and eight contests, including two international contests, five national contests and one Walnut Valley contest.

The contests are a major part of the Festival. Along with the National Flat Pick Guitar Championships and the International Finger Style Guitar Championships, the Walnut Valley Festival hosts the International Autoharp, National Mountain Dulcimer, National Hammered Dulcimer, National Bluegrass Banjo, National Mandolin and the Walnut Valley Old Time Fiddle Championships. Over the course of years, the contests at Winfield have attracted more than 5,600 contestants from all 50 states as well as many foreign countries including Australia, Brazil, Canada, Denmark, France, Scotland, Sweden, England, Germany, Italy, Japan, New Caledonia, and Switzerland. Well-known Winfield winners include Mark O'Connor of New York, New York, 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, Tennessee won the Walnut Valley Fiddle Championship in 1984. Steve Kaufman of Alcoa, Tennessee and Jason Shaw of Lincoln, Nebraska are the only three-time winners of the National Guitar Flat-Picking Contest, Kaufman having won in the years 1978, 1984, and 1986 and Shaw having won in 1993, 2004 and 2010. Jason Shaw is also a two-time winner in the Walnut Valley Old Time Fiddle Championship. In 2009, Bryan McDowell from North Carolina became the only contestant to win three contests in one year, Flat-Pick, Mandolin and Fiddle. Other Winfield winners include mandolin virtuoso Chris Thile, the Mandolin Champion in 1993 and Dixie Chicks fiddler Martie Erwin Seidel who placed second in 1987 and third in 1989.