“Wow, it sure is nice to come to one of these [cruise-ins] with a good crowd,” commented a participant who relaxed under a shade tree at the 2021 Thunder in the Park. Gary England manned England's Sound Machine as “Elvis” opened with the National Anthem. The crowd had some 200 vehicles to inspect, admire, and photograph while the sounds of “Achy, Breaky Heart” and other traditional favorites played in the background. One enterprising young man was selling his truck and revved the engine to a roar in keeping with the thunder theme and the pleasure of the crowd. Diane England and Brenda Sweet handled the registration booth and received over 100 toys and lots of monetary donations for the Under the Tree Project that provides toys for children at Christmas. Donors also received door prize tickets that granted them an opportunity to win Union County Opry tickets, free meals, and a variety of other goods.

When attendees had their fill of the cars, trucks, and tractors, they walked down toward Wilson Park to munch on the hotdogs and gyros, sip the lemonade, swirl the shave ice, and relish the fried oreos and funnel cakes. Then they found a place to sit and listen to Generation Gap perform their own rendition of rock, popular songs, and a little bit of country. The up and coming band showcased Josh Henley on drums, Michael Mlekodaj on guitar, and Trent Eller on bass. The headliner followed with Three Dog Celebration featuring Michael McMeel, formerly of Three Dog Night.

Chilren could ride the Shriner cars, bounce in the Bounce House, or slide on the granddaddy of all slides while they waited for the fireworks finale by Pyro Shows.

Thunder in the Park is an annual celebration held on the Saturday before Labor Day and hosted by the Union County Chamber of Commerce along with the City of Maynardville, Union County, and the Norris Lake Region as a free family event. GRIID, State Farm, First Bank, and Rocky Top IT sponsored the event.