[2] During most of the 20th century, the Hollywood entertainment industry preferred to film movies and television shows within the studio zone to reduce labor costs.

Conversely, anyone who wanted to start a career in the entertainment industry needed to move to Los Angeles to break into the studio zone.

[3] The studio zone's boundaries have expanded over the years, primarily to keep labor costs down and help keep Los Angeles as an attractive site to shoot productions.

[4] In 2010, additional locations were added: Agua Dulce, the entire community of Castaic (in addition to Castaic Lake), Leo Carrillo State Park, Moorpark, Ontario International Airport, Piru, and Pomona (including the Fairplex, of which a small portion is jurisdictionally in La Verne).

Places such as Pittsburgh, Pennsylvania; New Orleans, Louisiana; Atlanta, Georgia; and Vancouver, British Columbia, Canada have become popular—and cheaper—alternatives to filming in Los Angeles and New York City.