McDonaldland was the name of McDonald's 1970s advertising world populated by Ronald McDonald, Grimace, and the Hamburglar.
The fictional setting gave McDonald's a shared universe for television commercials, restaurant play areas, packaging, and promotional merchandise. Its characters personified menu items, restaurant themes, and playful conflicts designed to appeal particularly to children.
The best-known residents included Ronald McDonald, the Hamburglar, Grimace, Mayor McCheese, Birdie the Early Bird, and Captain Crook. Their designs and roles changed over time, but the McDonaldland setting linked them into one recognizable brand world.
McDonaldland is sometimes mistaken for the name of a restaurant format or a real theme park. It was primarily an advertising and character universe, even though McDonald's used its imagery in physical restaurant experiences.