The festivities caused some problems on the roads. Traffic was backed up on the 5 Freeway and on surface streets around midnight as people tried to get into the park.
Some Disney fans camped out before the park opened to be the first ones in line.
Woodland Hills resident Jessica Ashley arrived at 5 a.m. Wednesday and spent 24 hours at Disneyland.
"I just love Disneyland. I love the joy of just going on rides, having fun with my friends. It's really fun to me!" Ashley said. "I want to go back, but I'm really tired."
Kimberly Rice, of San Diego, said she was inside the theme park with her family for about 20 hours. She said one of the longest lines she waited in was for coffee.
The Walt Disney World Resort in Orlando, Florida, also participated in the special 24-hour event.
Disney is the parent company of ABC7.