Petrified Forest

Sonoma County’s Petrified Forest near Calistoga preserves one of California’s most unusual geological landscapes: the state’s only Pliocene petrified forest and some of the world’s largest petrified trees. Formed about 3.4 million years ago when an eruption at Mount St. Helena buried living trees, it preserves an ancient forest in stone and has provided evidence that redwoods once grew farther inland. Discovered in 1870 by Othniel Charles Marsh and later noted by Robert Louis Stevenson, it became a long-running family attraction after Ollie Orre Bockee acquired and expanded the property in the early 20th century. Restored after the 2017 fires, it remains both scientifically important and publicly accessible.

California · United States