The first Dairy Queen store opened in 1940 in Joliet, Illinois.
The store opened on June 22, 1940, after J.F. McCullough and his son Alex developed a soft-serve formula and worked with Sherb Noble to bring it to market. Noble had first tested the product at his ice-cream shop in Kankakee, Illinois, where customers bought more than 1,600 servings in just two hours.
The Joliet location became the first store to operate under the Dairy Queen name. It stood at 501 North Chicago Street and closed in the 1950s, but the building later received city landmark status. The early business relied on franchising to spread the soft-serve concept well beyond its original Illinois setting.
Chicago is a tempting answer because it is Illinois’s largest and best-known city, while Aurora and Rockford are also major Illinois communities. None was the site of the first Dairy Queen. Joliet’s location is the key historical distinction, even though the soft-serve product had been tested earlier in nearby Kankakee.