From the Guidebook:
Petaluma Adobe served as the center for General
Mariano Guadalupe Vallejo's 66,000-acre working
rancho from 1836-1846. It was once the largest privately
owned adobe building in Northern California; Vallejo sold
the building and surrounding acres in 1857. The Native
Sons of the Golden West acquired the Adobe in 1910 and
the State of California obtained it in 1951.
Plaque placed by the Sonoma Petaluma State Historic Parks Association and the Native Daughters of the Golden West Petaluma Parlor #222, July 11th 2006.