The 23-year-old Oregon woman who was last seen south of Half Moon Bay last week was found injured but alive by a pair of passersby Friday night and taken to a hospital after her Jeep went over a cliff near Big Sur, officials said.

A man and woman walking near Highway 1 in an unincorporated area of Monterey County found the missing woman with an injured shoulder Friday evening and called for help, said Monterey County sheriff’s Cmdr. John Thornburg.

Just before 7 p.m., personnel with the sheriff’s office rescue team, responding to the call for help, found Angela Hernandez’s 2011 white Jeep Patriot over the cliff, and Hernandez just below the car, walking and talking, Thornburg said.

It’s unclear how far the car traveled off the cliff, Thornburg said.

By 7:13 p.m., officials announced Hernandez was being taken to a nearby trauma center. Thornburg described her as alert when officers reached the scene.

He said officials are unclear when her car went over the cliff, but estimate she may have been there for days.

Personnel with California State Parks, Big Sur Fire and California Highway Patrol were still at the scene Friday night to determine what led up to Hernandez’s car going over the cliff.

Hernandez drove into Monterey County on Highway 1 about 9:30 a.m. on July 6, according to San Mateo County sheriff’s officials.

Her relatives told police they believe she may have taken a dangerous winding road over the coastal range south of Big Sur. Hernandez had been driving from Portland to her sister’s home in Southern California, according to family.

She was seen on surveillance camera footage from businesses along Highway 1, officials said.

Before deputies reviewed surveillance video, Hernandez’s last known whereabouts were in a parking lot behind a Safeway in Half Moon Bay. She texted her sister the morning of July 6 that she had slept there the night before and was getting back on the road, authorities said.

Investigators with the San Mateo Sheriff’s Office detected a signal last Saturday from Hernandez’s phone bouncing off a tower near Davenport in Santa Cruz County, roughly 40 miles south of Half Moon Bay. The signal disappeared by Monday.

Lauren Hernandez is a San Francisco Chronicle staff writer. Email: lauren.hernandez@sfchronicle.com Twitter: @LaurenPorFavor