The only prehistoric human remains uncovered in the Rancho La Brea area (the famous "Tar Pits") were those of La Brea Woman, found in 1914. Excavators uncovered a woman's skull and partial skeleton. She was determined, by more recent radiocarbon-dating, to have died approximately 10,220-10,250 years ago, making her one of the earliest identified human residents of Los Angeles County. She was believed to have been about 18-24 years old (others speculate about 25-30 years old). She stood about 4 feet, 8-10 inches (1.5 meters) tall. Wear on her surviving teeth indicate a diet of stone-ground meal. It is questioned whether she was originally from the area of the tar pits. Her skull structure suggests that she may have been from the Chumash people, although, this is debated. Another mystery was that her skull was found fractured, suggesting a wound or blow to the head that may have killed her. She might just be L.A.'s first known homicide victim. A broken grinding stone was found nearby, a common burial item among Southern California's aboriginal people.
The remains of a domestic dog were also found near to where La Brea Woman's remains were found. The animal was long believed to have been buried with her, speculated to be part of a ceremonial process surrounding her death. However, the dog's remains were radiocarbon-tested in 2015 and determined to be only about 3,200-3,400 years old and, therefore, not connected to La Brea woman. See Tar Trap: No Evidence of Domestic Dog Burial with “La Brea Woman”.
Source: The Page Museum at the La Brea Tar Pits (and thanks, Claire, for your notes!)
In 2009, forensic artist Melissa R. Cooper created a facial reproduction of what La Brea Woman's face may have looked like, based upon her skull structure.