McDonaldland was the fictional advertising world created for McDonald's characters and campaigns.
The setting gave Ronald McDonald, Grimace, the Hamburglar, Mayor McCheese, and other figures a shared environment. Instead of presenting each character in isolation, McDonaldland allowed McDonald's commercials to operate like a continuing children's fantasy setting populated by recognizable brand mascots.
The campaign began in the early 1970s and was used in television advertising, restaurant promotions, playgrounds, and merchandise. Its bright visual style linked the characters to McDonald's menu items and restaurant experience without requiring every advertisement to explain who they were.
McDonaldland is a branding concept, not the name of a real McDonald's theme park or a standard restaurant format. That distinction helps separate the fictional advertising world from later branded playground and promotional names.