2021 Map of Keystone

About this map

Keystone sits at the junction of La Grande Rd and Green Springs Rd, serving as a central point in this transition from the Central Valley foothills toward the Sierra Nevada. The landscape is defined by its water management and aviation history, notably featuring the Kistler Ranch Airport and the massive subterranean engineering of the Hetch Hetchy Aqueduct, which cuts diagonally across the southwestern corner of the quadrangle. In the north, the Stanislaus River marks the boundary between Calaveras and Tuolumne counties, while the eastern edge is dominated by the Red Hills and Rushing Mtn. This area reflects a classic California ranching and utility corridor, where long-established routes like Tulloch Rd and Rock River Rd weave between seasonal drainages such as Owl Cr and Mountain Pass Cr.