The Bay Area’s Mystery Walls

For more than a century, Bay Area residents have been puzzled over the existence of stone walls scattered across the East Bay, beginning in San Jose and continuing north into the hills of Berkeley. These structures appear to have been built from hand, some in long straight lines, some in angular forms, and others in rectangles or circles. Their origins, however, remain a mystery. 

Many researchers believe that they were constructed by indigenous peoples of the area, namely the Ohlone or Miwok tribes, for ceremonial or territorial purposes, whereas others suggest they served as animal enclosures for early European settlers. The first mention of these walls, in an 1896 issue of the San Francisco Chronicle, suggests that they were the work of “a long-forgotten race”. 

These Native American tribes, who have populated the Bay Area for about 10,000 years, however, have given no indication that they have built these long walls. The more likely consensus, thus, is their possible connection to the early European settlers. Their origins, however, have yet to be studied formally. 

The most well-preserved sections of the wall are located near the summit of Monument Peak in Ed Levin County Park, though it takes a difficult 9-mile loop to find them. The Sierra Vista Open Space Preserve, however, has a preserved section only half a mile from the parking lot. Exploring these mystery walls offers a unique Bay Area opportunity to connect with the region’s indigenous history and ponder their historical significance. While their origins remain unknown, they remain an important reminder of the rich and diverse cultural heritage of the Bay.