Around ten million years ago, during pre-historic times (Miocene), the mountains are thought to have been densely forested in Mendocino Cypress (Cupressus pygmaea).

According to Barrett (Pomo, p. 269), there was a Yukian Wappo village, Maiya'kma, one mile south of present day Calistoga.

Serro de los Mallacomes (Mount Saint Helena) is shown on a diseño of the Rancho Caymus grant (1836).

Later the name appears in the title and on the diseños of the Rancho Mallacomes y Plano de Agua Caliente or Moristul land grant, dated September 3, 1841, and October 11 and 14, 1843.

Located in the Mayacamas mountain range is The Geysers, the world's largest and most developed geothermal field.