The scene was reportedly so grisly that several local TV stations were forced to blur out images captured by their helicopter cameras.
Five of the bodies were found by deputies from the San Bernardino County Sheriff’s office on Tuesday evening at a dirt crossroads outside the community of El Mirage.
The sixth was found Wednesday morning, according to the sheriff’s spokesperson Mara Rodriguez.
Ms Rodriguez said that investigations into the incident are ongoing and that authorities are yet to determine how the people had died or whether they had been shot.
The area, about 50 miles northeast of Los Angeles and about 20 miles northwest of Victorville, is so remote that the San Bernardino Sheriff’s Department called in help from the California Highway Patrol’s Aviation Division to find the scene, Ms Rodriguez said.
“It’ll be several hours still before we are ready for anybody to be removed from the scene,” she said, adding that the coroner’s investigators will be called in then.
TV crews arriving on Tuesday night reported seeing two vehicles at the crime scene. Overhead footage from TV stations showed a dark blue SUV with a passenger window blown out and another door open, with part of the image blurred.
The footage showed numerous yellow evidence markers near the dirt crossroads, in scrubby desert land that stretched for miles. Yellow tape blocked access from the nearest paved road.
Members of the department’s specialized investigations division were brought in to conduct a homicide investigation, according to an email from sheriff’s spokeswoman Gloria Huerta.