The epicenter of the 9:23 a.m. quake was located nearly 4 miles north of Placentia and 4 miles south-southeast of Rowland Heights, the USGS said. Its depth was measured at 4.35 miles.
There were no immediate reports of injuries or major damage.
Tesha Carter said she felt the temblor, which she described as a "quick jolt," in Buena Park.
Other ABC7 viewers said they experienced the quake in Yorba Linda, Fullerton, La Habra and Monterey Park.
In a Facebook post, Kathleen Lopez said she felt the earthquake in Diamond Bar.
"My dog was laying on the couch with me and he didn't even move," she said.