What part of the US is known as Tinseltown?

Tinseltown is a slang term for Hollywood, a district in the city of Los Angeles that has become famous as the cradle of the American film industry. Because of Hollywood's association with the film industry, the district has become almost a magical place for some Americans, who romanticize both the region and the people who live there. The term is also used to describe films, often scathingly, to dismiss them as shallow.

Source: United States Now