<P> Hill Valley, California, is the fictional town in Northern California that serves as the setting of the Back to the Future trilogy and its animated spin - off series . In the trilogy, Hill Valley is seen in four different time periods (1885, 1955, 1985 and 2015) as well as in a dystopian alternate 1985 . The films contain many sight gags, verbal innuendos and detailed set design elements, from which a detailed and consistent history of the area can be derived . </P> <P> The name "Hill Valley" is itself a joke, being an oxymoron . However, an early script for Back to the Future Part II mentioned that Hill Valley was named after its founder, William "Bill" Hill . </P> <P> For Back to the Future, the producers considered filming the town square scenes in the real city of Petaluma, California, but soon realized it would be prohibitively expensive and impractical to alter a real place to suit the different eras . Instead they filmed it on the Universal Studios backlot, where they had more control . The main location, once called Mockingbird Square after the 1962 film To Kill a Mockingbird but now known as Courthouse Square, had been used for many films and television shows . One notable example is the very first episode of the sci - fi series The Twilight Zone, called "Where Is Everybody?" in 1959 . The Hill Valley courthouse can also be found in the movies Bruce Almighty, Gremlins, Bye Bye Birdie, Sneakers, The Offspring's music video "Why Don't You Get a Job?", an episode of Major Dad entitled "Who's That Blonde" and even in an episode of Buffy The Vampire Slayer . The clock tower itself was a removable addition, one of many ways in which the Courthouse building has been redressed over the years to suit the needs of a production . </P> <P> Many of the cars that appear in the 2015 scenes are either modified for the film or concept cars . Examples include Ford Probe, Saab EV - 1, Citroën DS 21, Pontiac Banshee Concept, Pontiac Fiero and Volkswagen Beetle . Cars reused from other science fiction films include the "Star Car" from The Last Starfighter (1984) and a "Spinner" from Blade Runner (1982). Griff's car is a modified BMW convertible . </P>

Where was the clock tower in back to the future filmed