Sonoma Mountain, or Oona-pa'is in Coast Miwok, is a prominent peak in southern Sonoma County whose geologic origins reach back to Miocene uplift from an ancient Pacific seabed. Its varied slopes support distinct habitats, from oak woodland and occasional redwood groves to chaparral, grassland, and oak savannah, with creeks, wildlife, and vineyards on its flanks. The mountain is closely linked to Jack London, who bought one thousand acres on its eastern slope in 1910 for Beauty Ranch; that land later became Jack London State Historic Park, home to the ruins of Wolf House. Additional protected lands, trails, research areas, and a viticultural area have expanded its recreational, scientific, and agricultural significance.