Authorities hope the likeness will lead to tips that will help identity of the woman, who they say was killed within the last 6-12 months.
A sheriff's department patrol officer found the victim's leg bone off state Highway 128 in Napa County near the Monticello Dam on May 10, Detective Todd Hancock said.
"He didn't identify it immediately but he was very suspicious. An expert identified it as a leg bone," Hancock said.
The rest of the woman's remains were found above ground nearby.
Bay Area facial reconstruction artist Gloria Nusse created the 3-D sculpture of the woman from the shoulders up.
"It's very recognizable to anyone who knew her," Hancock said. The victim is a black woman between 35 and 50 years old. She was 5 feet 5 inches to 5 feet 6 inches with an average build, according to the sheriff's office.
The victim had short, curly, natural light-colored hair with a weave attached. She had a stud, nose or lip piercing and extensive dental work. Her teeth were in good repair, the sheriff's department said.
The woman had acrylic, French-cut fingernails and was partially clothed in an olive or green-colored, short-sleeve polo-style shirt.
A pelvic exam indicated she had given birth to at least one child, and degeneration of her lower spine suggests she may have had lower back problems, authorities said.
The sheriff's department is not disclosing how the woman was killed. The woman has not been matched to any missing persons cases in the western United States, Hancock said.