Like many residents in and around Fontana, 33-year-old Regina Ignacio was awoken early Wednesday morning by shaking.
"I was in bed. ... I knew it was an earthquake," Ignacio said. "They're just scary because you don't know if it's going to get worse."
The magnitude 4.4 earthquake struck at 1:35 a.m. and was centered about three miles north of Fontana and about five miles northwest of Rialto.
There were no immediate reports of injuries or major damage. Some residents said items fell off their dressers, while others took to Twitter to describe minor damage inside their homes.
Angie Garcia, 26, lives in Rancho Cucamonga and said the earthquake woke her up out of bed and "did knock my mirror down."
She added that it "didn't feel like a terrible earthquake."
But Alysha Griggs of Rialto said the earthquake felt large to her, adding that it lasted about 10 seconds and "shook the whole house."
"And then my dog started going crazy," she said. "It felt pretty big."