The incident happened about 11 p.m. Tuesday near Ventura Place and Laurel Canyon Boulevard in Studio City.
Los Angeles Police Det. Karen Crawford said a man approached the victim, threw her to the ground and raped her in what is typically a highly-trafficked area.
"There are always people out and about, but there's always dark, hidden areas," Crawford said. "There's bushes, there's shadows."
Authorities described the suspect as an African-American man, about 40 to 45 years old, with a tattoo on his right forearm. He was allegedly wearing blue jeans, a blue shirt and a wedding band.
Locals said they couldn't remember hearing of a crime like it in the area.
"It's pretty scary," said Michal Feldmar. "You think of Studio City as a safe neighborhood. Lots of families."
Crawford said it had been about a decade since they investigated a similar incident in the area.