In 1834, Mariano Guadalupe Vallejo was sent from San Francisco, by the Mexican Government, to the area to accomplish three things: to secularize the San Francisco Solano Mission in Sonoma, to colonize the area by starting a pueblo (Sonoma), and to be near the Russian Outpost at Fort Ross. He was given his first land grant of 44,000 acres (later supplemented with another 22,000 acres) as a reward and to further encourage his leadership. He chose a hilltop for his Petaluma Adobe rancho and factory. The operation needed to be large in order to support Vallejo's military command in Sonoma, as they did not receive adequate support from the government.
The Adobe served as the center of General Mariano Guadalupe Vallejo's 66,000-acre (100 square miles) working ranch between 1836-1846. Made from adobe brick and Redwood, its design is typical of Hispanic Architecture. The construction of the building is a reflection of the increasing trade in the area. The building began with tree nails and rawhide lashings to hold the beams together and moved to iron nails, hinges, glass windows, and a hand split shingled roof.
The rancho headquarters at Petaluma Adobe were unusual because many working areas were combined into one large building rather than a number of smaller outbuildings. There were between 600-2,000 people working at the Adobe, but not all of them lived within the building. The workers of higher status and supervisors would have lived upstairs. There was a Native American village adjacent to the creek. The main economic activity of the rancho was based on the hide and tallow trade. As well, the rancho produced many crops, and grain was traded in large quantities.
Although Vallejo could not come out here from his home in Sonoma as often as he wished, he was proud of his working ranch. The Adobe structure was not completed when Vallejo was taken captive during the Bear Flag Revolt in 1846. By the time Vallejo was released months later, the Gold Rush had driven labor prices up and squatters had taken over portions of the land. The ranch would never operate on the scale that it had previously. Vallejo eventually sold the building and some property in 1857 after attempts to lease it and make a profit failed.
The Petaluma Adobe building was once considered for the site of the University of California, but after a survey and discussion, another site was chosen. The Native Sons of the Golden West purchased the Adobe in 1910 and preserved it until the State bought it in 1951. Today, the State owns a small portion of what once a vast rancho and the largest privately owned Adobe building in California. The Adobe was officially registered as California State Historical Landmark #18 in 1932 and in 1970 became a registered National Historic Landmark.