Before it was a park frequented by tourists and school groups, Petaluma Adobe was a working ranch owned by Mariano Guadalupe Vallejo, a Mexican general sent to oversee Mexico's holdings in Alta California. The ranch made its money by selling cow hides and tallow, used for candles, as well as wheat and other crops.
But in 1846, Vallejo was arrested during the Bear Flag Revolt and the ranch fell into disrepair, especially when squaters, who had arrived for the Gold Rush, began settling on the property. Vallejo sold the ranch in 1857. It became a California Historical Landmark in 1932, and today is overseen by the state Department of Parks.
Petaluma Adobe is open daily, and has an informative museum on its premises. It also offers volunteer opportunities such as, guiding tours, gardening, taking care of animals, and conducting bike patrol of the 41 acre property.