California is a state in the United States of America.
Percy Jackson, Annabeth Chase and Grover Underwood go to Los Angeles, the entrance to the Underworld to convince Hades to return Zeus’ Master Bolt and Sally Jackson. After escaping the three end up on Santa Monica Beach.
Camp Jupiter, located near San Francisco, is present at the start and conclusion of the book.
Camp Jupiter is the setting of the first few chapters of the book.
Apollo, Meg McCaffrey and Grover travel around Southern California for the book. They visit Palm Springs, Malibu, Los Angeles, Pasadena, and Santa Barbara. At the end of the book, Apollo and Meg travel on a plane to the Bay Area.
- Southern California is colloquially known as "SoCal".