McDonald's introduced the fictional world of McDonaldland in 1971.
McDonaldland was a fantasy setting created for McDonald's advertising and promotions. It featured colorful characters and locations built around the restaurant's food and brand identity, including Ronald McDonald, Mayor McCheese, the Hamburglar, and the Fry Kids.
The campaign gave McDonald's a connected cast of characters rather than relying only on a single mascot. This approach was especially suited to children's advertising and helped turn visits to the restaurant into part of an imaginative brand world.
McDonaldland characters changed over time, and not every character was introduced in exactly the same year. That is why the world itself should be distinguished from individual figures such as Ronald McDonald, who first appeared earlier, in 1963.