A hiker found the remains in an area below Star Hill Road, west of the El Corte de Madera Creek Open Space Preserve in unincorporated San Mateo County, west of Woodside.
Emergency personnel could not recover them until Monday due to the rugged terrain, San Mateo County sheriff's Lt. Wes Matsuura said.
Despite media speculation that the remains could be of San Carlos resident Douglas May, 55, a hiker who went missing in that area in July, a spokesperson at the San Mateo County Coroner's Office on Wednesday declined to speculate on whose bones were found.
The bones are being tested for DNA to determine the person's identity, she said.
Mr. May never came home from a hike in the Skeggs Point area of unincorporated San Mateo County on July 16, 2009, which is within a few miles of where the bones were found. Family members contacted the Sheriff's Office when he hadn't returned.
A sheriff's deputy found Mr. May's car just before 1 a.m. on July 17 in the Skeggs Point parking lot. Skeggs Point is part of the Midpeninsula Regional Open Space District, located on state Highway 35, south of state Highway 92 near Woodside.
Authorities in July said they did not suspect foul play but believed Mr. May was lost or injured.
Sheriff's office spokeswoman Sgt. Linda Gibbons said at the time Mr. May had had medical problems in the past but declined to give further details.
More than 40 officers, multiple aircraft, at least four mounted patrols and K9 teams searched for Mr. May in off-trail and hilly areas after he was reported missing.