The fictional world created for McDonald's character-based advertising was called McDonaldland.
McDonaldland gave McDonald's mascots a shared setting and story framework. Ronald McDonald appeared there alongside characters including Grimace, the Hamburglar, Birdie the Early Bird, and Mayor McCheese. The setting helped the company turn separate promotional characters into a recognizable branded universe.
The campaign was designed especially for children and appeared in television commercials, restaurant promotions, playground equipment, and other marketing. Its bright visual style made McDonald's advertising distinctive during the 1970s and 1980s.
McDonaldland is sometimes used loosely to mean the characters themselves, but the name specifically refers to the fictional world. The individual mascots have separate names and roles. The setting also should not be confused with a physical theme park: it was primarily an advertising and merchandising concept associated with McDonald's restaurants.