Mammoth Rocks is a prehistoric natural site in Sonoma County that preserves a series oversized stones that are believed to have been used as scratching posts for Columbian mammoths during the last Ice Age. The blueschist stones span a height variation of 10 to 14 feet above the ground, an approximate shoulder height for mammoth species. Their faces feature the same types of gravel scratches as are found on rubbing rocks for modern-day African elephants, with wear and tear that is too frequent and methodical to be accomplished by natural means. As a result, scientists believe that the broader region was part of a larger mammoth territory during the Ice Age, with a large prairie area and what is believed to be an ancient watering hole located nearby.

Duncans Mills, California, 95430

Plan Your Trip

Get Ready to Go!

Need some more help?


Read our Reservations & Travel Planning Tips guide.