The following is an excerpt from the Wikipedia entry for the film A Face in the Crowd, a 1957 film starring Andy Griffith, Patricia Neal and Walter Matthau, directed by Elia Kazan.
“Most of the film’s interiors were shot in New York at the Biograph Studios in the Bronx. The most involved location shoot was in Piggott, Arkansas (the fair and baton-twirling competition scenes). Five thousand extras were sought, to be fed and paid $1 hourly for a mid-August day’s work. Sixty baton twirlers were rounded up from NE Arkansas and SE Missouri, and musicians from six different high school bands were assembled. Remick reported spending two weeks in Piggott living with teen twirler Amanda Robinson and her family, working on her twirling and local accent. Some of her baton twirling scenes used a double. At the Piggott location shoot some 380 dogs were assembled from Missouri and Arkansas for the scene following Rhodes’ first mass-action call on his audience: to take their dogs to the home of a local sheriff who was running for higher office – Rhodes opining that people should first find out if a candidate is worthy of the office of ‘dog catcher’.”
I was nine years old in 1957 and not much interested the movies. But it sounds like the location shooting in Piggott was a pretty big deal. I struggled to identify the twirler and finally concluded it was Sandra Wirth, even though she isn’t listed in the cast on iMDB. Now I’m wondering if it might be Amanda Robinson.