California is home to many well known and iconic Amusement and Theme Parks.  Knott's Berry Farm in Buena Park is America's 1st Theme Park, which started due to the popularity of Mrs. Knott's Chicken Dinner Restaurant.  And of course, the original Disneyland was the first of many theme parks now run by Disney around the world, placed in the center of the Southern California region.

In Northern California, California's Great America is located in Santa Clara.  It's a park that has changed over the years, opening as Marriott's Great America in 1976 (as a traditional Amusement park) and now has added thrills and a water park -- all for one admission price.  It is currently owned and operated by the Cedar Fair Entertainment Company and shares its parking lot with the new Levi's Stadium -- home of the San Francisco 49'ers Football team plus other sports and entertainment events,

https://www.cagreatamerica.com/

Also in the Bay area, Six Flags Discovery Kingdom in Vallejo is a park that started as an aquatic animal park, and has now morphed into a park with a zoo with many land mammal's like elephants and giraffes, but still featuring Dolphins and Killer Whales, plus a selection of roller coasters and other rides.  The park opened in 1968 in Redwood City and then moved about 55 miles to Vallejo in 1985, changing its name from'Marine World' in 2007.

http://www.sixflags.com/discoveryKing...

The newest park in Northern California is a kids-friendly park named Gilroy Gardens (formerly Bonfante Gardens) located in Gilroy.  The main theme is horticulture, as it is home of the famous "Circus Trees".  The grounds are beautiful, plus there are a bunch of rides that all can enjoy, but it's mainly for families. It is managed by the Cedar Fair Entertainment Company.

http://www.gilroygardens.org/

A bit smaller, but well known is the Santa Cruz Beach Boardwalk, a traditional amusement area found along the Pacific Ocean. Also in the area is a small roadside attraction called the Mystery Spot, which is worth a stop if you have a rental car.

http://www.beachboardwalk.com/

 

Then there is a large selection of Amusement/Theme Parks in Southern California.

Going from North to South.

Six Flags Magic Mountain is a large amusement park packed with thrill rides. It has 18 roller coasters (more than any other location in the world) and many other rides and attractions, it is most famous for being the "Walley World" that the Griswold's wanted to visit in "National Lampoon's Vacation" movie. Opened in 1971, it is celebrating over 40 years of keeping people of all ages happy. It also has a lot of Family attractions, including lands based on Bugs Bunny and his Friends, and other areas. It, also, has a water park next door, Hurricane Harbor (Separate admission required.)

http://www.sixflags.com/magicMountain...

Universal Studios Hollywood opened in 1964, and is most well known for the Studio Tour that takes you into the backlot of the studio for a 'drive by' of famous exterior sets and studio buildings.  Also included in this 50-minute attraction are a number of 'special effects' that the tram drives through to the delight of those onboard.  The Park also has movie-themed rides and live shows. In 2016, they opened up the new "Wizardly World of Harry Potter" section of the park. There is a shopping, dining and entertainment complex next door called Universal CityWalk.

Find Discounts Universal Studios Hollywood Discounts

http://www.universalstudioshollywood....

The Knott's Berry Farm is home of America's 1st Theme Park.  Adjacent to the theme park is a water park (Knott's Soak City Orange County), and a shopping and dining area called California Marketplace, whose main tenant is the World Famous Mrs. Knott's Chicken Dinner Restaurant. These three attractions are dubbed Knotts Southern California Resort.  Also located on the property is a Hotel, and a true recreation of Independence Hall.  Knott's Berry Farm has one of the best rated wooden roller coasters, Ghostrider, along with many other coasters, plus much more, including Camp Snoopy for kids. 

http://www.knotts.com

Disneyland, the park built by Walt, is the most famous Theme Park location in the state.  Currently the location has three Disney-owned hotels, a shopping and dining mall called Downtown Disney plus two Theme Parks. Disneyland is the famous one upon which Walt Disney risked his reputation and empire.  It was a good bet, as the Park has been very popular since opening day, July 17th, 1955.  A second Park, Disney California Adventure opened in February of 2001.  It has grown and changed since the opening. A major addition opened in the Summer of 2012 that addressed some of the major issues but it is still smaller and has fewer attractions than Disneyland Park.

http://www.disneyland.com

In North San Diego County, the LEGOLAND Resort is located in Carlsbad.  This park is mainly designed for kids and pre-teens, as well as for LEGO fans of all ages. You will not find many thrills here, but you will find a lot of rides and attractions that the family can enjoy together. Consists of three different gates, the main "ride" park, a water park, and the SEALIFE Aquarium.

http://california.legoland.com/

Then there is SeaWorld San Diego, which opened in 1964 as an marine zoological park along the edge of Mission Bay.  It has grown and now offers rides and attractions, along with many marine animal shows.

http://seaworldparks.com/en/seaworld-...

Some would call the San Diego Zoo and the San Diego Zoo Safari Park as Theme Parks, as they both offer rides and other types of attractions, such as Ziplines along with the traditional animal displays.

http://www.sandiegozoo.org/