1997 Map of Detert Reservoir

About this map

Collayomi Valley anchors the northern reaches of this landscape, where the settlement of Middletown sits near the base of St Helena Creek. The topography is defined by significant quicksilver mining history, evidenced by a high density of named workings including the Oat Hill Mine, Mirabel Mine, and Silverado Mine scattered across the ridges. The eastern portion is dominated by the Detert Reservoir and the drainage of Bucksnort Creek, while the southern boundary includes the dramatic verticality of The Palisades and the protected lands of Robert Louis Stevenson State Park. This terrain reflects the complex geology of the Mayacamas Mountains at the intersection of Lake, Napa, and Sonoma counties, showcasing the transition from valley floor agriculture to high-altitude mineral extraction sites like the Corona Mine and Magnolia Mine.