2018 Map of Tassajara

About this map

Tassajara serves as a central point in this part of the Diablo Range, where the boundary between Contra Costa and Alameda counties meets. The landscape is defined by a dense network of ridges and canyons, including Riggs Canyon and Collier Canyon, which are crisscrossed by a complex system of fire roads and recreational paths such as the Highland Ridge Trail and Volvon Loop Trail. A notable concentration of water features like Sycamore Spring and Cottonwood Creek drain the slopes of the Black Hills. This region maintains a distinctly rural and conservation-oriented character, with large expanses like Round Valley and the Cañada De Los Poblanos preserved as open space. Local history is etched into the topography through names like Old School Road, signaling the infrastructure of early ranching communities.