McDonald's used the fictional world McDonaldland for characters such as Ronald McDonald and the Hamburglar.
McDonaldland was an advertising setting created for McDonald's campaigns in the early 1970s. It presented the restaurant's characters as residents of a playful world filled with visual references to McDonald's products, restaurants, and branding. Ronald McDonald served as the central figure within that setting.
The world included characters such as the Hamburglar, Mayor McCheese, Grimace, Birdie the Early Bird, and Officer Big Mac. Their designs and roles changed over time, but together they created a recognizable family-oriented advertising universe.
McDonaldland was not a separate theme park or restaurant chain. It was primarily a fictional setting used in commercials, promotional materials, and merchandise. That distinction helps separate the name from other McDonald's marketing phrases involving worlds, playgrounds, or themed experiences.