Lauren "El" Cho was last seen on June 28, walking away from the home where she had been staying with her former partner.
Air and ground searches have been conducted since Cho's disappearance, but so far there's been no sign of her.
Cho is described as 5 feet 3 inches tall, weighing 110 pounds, with black hair and brown eyes. She was last seen wearing a yellow T-shirt and jean shorts.
"We're hoping that will jog somebody's memory and provide more information for our investigators," said Gloria Huerta, spokeswoman for the San Bernardino County Sheriff's Department.
"Missing person" flyers have been posted in and around Yucca Valley and Morongo Valley.
Anyone with information about the case is asked to call the Sheriff's Department's dispatch center at (760) 956-5001 or Detective Ables at (760) 366-4175.
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