The cat was seen in the vicinity of 900 North Cabrillo Highway at about 2 a.m., county officials said.
The sighting was reported to the San Mateo County Sheriff's Office and deputies searched the area, but they did not find the animal, officials said.
Mountain lion sightings are common in San Mateo County, and anyone who encounters one should stay away from the animal and call the sheriff's office.
In the event of a confrontation, experts advise facing the animal, trying to appear as large as possible, making noise and throwing objects at the cat.
More information about mountain lions can be found online at www.keepmewild.org.