Yes. Disney's California Adventure is just across the way from Disneyland. There is a plaza between the two, but standing in line for one you can clearly see the other. However, a ticket for Disneyland won't get you into Disney's California Adventure on the same day without a ParkHopper option.
Disneyland changed its name to "Disneyland Resort" in 2001, with the opening of Downtown Disney, Disney's California Adventure (now Disney California Adventure) and the Grand Californian Hotel.
Disneyland and Disney's California Adventure
No, there are only two theme parks at Disneyland Resort: Disneyland and Disney California Adventure.
There are only two theme parks in the Disneyland Resort in Anaheim, CA: Disneyland Park and Disney California Adventure.
Disneyland Resort - 2012 Disney's California Adventure Park 1-3 was released on: USA: December 2012
Disney's California Adventure opened on February 8, 2001, 46 years after the opening of Disneyland. They are both part of the larger Disneyland Resort (and have been since the opening of California Adventure).
The six areas that are part of the Disneyland resort are the Disneyland theme park, Disney's California Adventure theme part, Downtown Disney District, The Disneyland Hotel, Disney's Grand California Hotel and the Paradise Pier Hotel
There are two Disney parks in Anaheim, California: Disneyland Park and Disney California Adventure Park. Disneyland Park, the original Disney theme park, opened in 1955, while Disney California Adventure opened in 2001. Together, they form the Disneyland Resort, attracting millions of visitors each year.
Disneyland Resort in Anaheim, CA only has two theme parks, Disneyland and Disney California Adventure.
At Disneyland and Disney's California there are 178 rides all together and 56 rides at California adventure
Before Disney California Adventure, directly across from Disneyland Park was the original Disneyland Parking lot, dating back to opening day, 1955. However, it was torn down and transformed into the then-called "Disney's California Adventure" in 2001. Along with the addition of the Downtown Disney District and two more Disney-owned hotels, this heralded the shift from "Disneyland" to the "Disneyland Resort" as we all know it today.
2007 Disneyland Resort in Anaheim California. Walt Disney World Resort, Orlando Florida. Tokyo Disney Resort, Tokyo. Disneyland Resort Paris, Paris. (Formerly EURO-Disney) Hong Kong Disneyland Resort, Hong Kong.