The Hill Valley Courthouse, clock tower and square all return in Back To The Future Part II, the area was transformed into it's 2015 state and fimed for the movie as you can see in the Video.Sadly much of the Hill Valley's Courthouse Square was destoryed in a fire on 1st June 2008, however the courthouse survived with minimal damage.
The site used for filming Marty pulling up outside the Lyon Estates sign when he has just arrived in 1955 to find his home hasn't been built yet was shot here. Please note: this is private property.The stone-looking Lyon Estates entrance gates, complete with lion statues, is a prop that can be seen at Universal Studios and survived the 2008 fire.
The site of Oak Park Cemetery is in fact on land occupied by the Valero Refinery in Wilmington, CA. The area was vacant at the time of filming and dressed to look like a cemetery with ominous smoking towers from the refinary in the background. It was since been built on.
The tunnel used for the Hoverboard chase between Marty and Biff is near Griffith Park on the same road as the Start Line used in Back To The Future Part I (1985).
Hill Valley High School or as it's really known Whittier High School, Philadelphia Street, Whittier, CA, real-life famous ex-students include Richard Nixon.
Hill Valley High School, where in Back To The Future Part II archive footage from the first film shows George McFly knocking out Biff Tannen (again!). This area was revisited for filming the sequel and is actually at Whittier High School located on Philadelphia Street, Whittier, CA
Inside the hall (on the right) is where the Enchantment Under The Sea Dance took place in 1955. You can see the double exit doors on the gymnasium. The Church is Hollywood United Methodist Church at 6817 Franklin Ave, Los Angeles with it's famous AIDS ribbon.
Marty McFly's house is really on Roslyndale Avenue, Pacoima, CA.
Biff Tannen's 1955 house. In reality it's located on Bushell Avenue in South Pasadena, California.
Doc Brown's house in 1955 is actually the Gamble House (of Proctor & Gamble) 4 Westmoreland Place, Pasadena, CA and it is open to the public so you can take a look around if you're ever in Pasadena!