1993 Map of Detert Reservoir

About this map

The rugged boundary between Lake, Napa, and Sonoma counties is dominated by the mercury and silver mining legacy of the Mayacmas Mountains. This 1993 revision reveals a landscape defined by historic extraction, featuring numerous workings such as the Oat Hill Mine, Silverado Mine, and Mirabel Mine. The southern portion of the map is largely occupied by Robert Louis Stevenson State Park, preserving the high elevations of the range including The Palisades and Table Rock. To the north, the terrain transitions into the ranch lands of Guenoc and the Collayomi Rancho, where the Detert Reservoir and several landing strips service the local area near Middletown. The intricate network of creeks, such as St Helena Creek and Bucksnort Creek, illustrates the complex drainage patterns feeding into the larger valleys below these volcanic peaks.