Rancho Petaluma was a land grant given in 1834 by the Mexican government to Mariano Guadalupe Vallejo, a prominent military leader and politician. Located in what is now Petaluma, California, the ranch covered approximately 66,000 acres and was primarily used for cattle ranching and agriculture. The ranch played a significant role in the development of the region, contributing to the local economy and settlement patterns. Today, remnants of Rancho Petaluma can be seen in the historical architecture and cultural heritage of Petaluma, which has evolved into a vibrant community.