The San Andreas Fault is a major geological fault in California, known for its significant role in the state's seismic activity. It stretches approximately 800 miles and is famous for being the boundary between the Pacific Plate and the North American Plate, making it a focal point for earthquakes in the region. This fault has been the site of numerous significant earthquakes, including the devastating 1906 San Francisco earthquake. Understanding the San Andreas Fault is crucial for earthquake preparedness and risk management in California, as it continues to pose a threat to the densely populated areas nearby.