Sanner was hiking on Mt. Tamalpais and was reported missing by her father around 2:30 p.m. Thursday.
She was last seen near the Mountain Home Range Inn a mile east of the Pantoll Ranger Station, Marin County sheriff's Lt. Doug Pittman said.
Her body was found at 5:30 p.m. Thursday along Fern Creek below and west of the Matt Davis Trail on Mt. Tamalpais, Marin County coroner's office Lt. Keith Boyd said.
Sanner was identified through fingerprints and an autopsy is scheduled for Monday, Boyd said.
The cause and manner of her death are under investigation, but there is no apparent connection to Sanner's death and the death of Magdalena Glinkowski, 33, of Menlo Park, Boyd said.
Glinkowski left a note on March 30 stating she was going for a hike. Her car was found April 4 near the Pantoll Campground, and security camera footage showed her walking across the parking lot.
A man who was trail running the day Glinkowski disappeared told the Marin County Sheriff's Office he saw Glinkowski's photo in the media and realized he might have seen her, the sheriff's office said.
Search and Rescue teams resumed the suspended search for Glinkowski and found her body on April 12 around 9:25 a.m. down a steep slope in a drainage area about a half-mile from the Bootjack parking lot where she was last seen, the sheriff's office said.
The sheriff's office said Glinkowski's autopsy showed no visible signs of trauma, and the cause and manner of her death are pending toxicology tests.