State Route 12 is a state highway in California that runs approximately 80 miles through the northern part of the state. It connects the cities of Vallejo and Stockton, passing through scenic areas such as the Suisun Marsh and the California Delta region. The route serves as an important transportation corridor, facilitating travel and commerce in the area. It features a mix of urban and rural landscapes, providing access to various attractions, including parks and recreational areas, making it a vital link for both residents and visitors.