Around 9 a.m., the hiker and another man drove to the Bell Station area near the 1400 block of Pacheco Pass Highway, in unincorporated Santa Clara County just outside of Gilroy, and began hiking up rocks and cliffs, sheriff's officials said.
Around 4:40 p.m., sheriff's deputies were notified that the two hikers had fallen off a cliff. One had reportedly had suffered major injuries.
Deputies, working Cal Fire crews, found that man dead near the base of the cliff, sheriff's officials said. The other hiker was taken to a hospital to be treated for his injuries.
The hikers' names have not been released.
Anyone with information about the case is asked to call Santa Clara County sheriff's Detective Sgts. Ryan Elder or Julian Quinonez at (408) 808-4500, or an anonymous tip line at (408) 808-4431.