Calhoun County Tractor Pulls Calhoun County Expo The Calhoun County Expo presents Tractor Pulls Sunday, May 30th, at the Calhoun County Fairgrounds in Rockwell City, starting at 1 pm! Check out….the Super Field tractors, 3000 RPM Tractors, Altered Farm Tractors Street stock trucks, diesel trucks, semis, local farmer tractors and more. Admission is $8 for adults and $4 for children. Enjoy the beer garden with ice cold beverages and food stand on the grounds, Smoking Grumps.