Liberal Arts City

Liberal Arts City or Arts and Sciences City (学芸都市) is a huge artificial island that exists on the coast of California, United States. Originally made as a set for a Hollywood movie, it was later converted into a seaside themed amusement park.

Background
20 years before the events of Toaru Majutsu no Index, an American Hollywood filmmaker designed and made a huge artificial island as a setting for a movie. At the end of the movie's filming, comments were made regarding the waste of dismantling such a huge effort made by the crew. Due to this, rather than being destroyed the island was reborn as a seaside resort and theme park.

Toaru Kagaku no Railgun SS: Liberal Arts City
Although not shown in the original Toaru Majutsu no Index series, the Liberal Arts City is the main setting of the side story Toaru Kagaku no Railgun SS: Liberal Arts City, which takes place soon after the events of the Three Stories Arc.

Hawaii Invasion Arc
It is revealed that Olay Blueshake backed Liberal Arts City in their experiments to develop supernatural power as part of Knowledge 12, of which she was the major investor. The experiment ending in catastrophic failure and Knowledge 12 being shutdown is mentioned by Olay to Roseline Krackhart as one of the reasons why she wants to turn the United States into a theocracy.