The history of Carneros is inextricably linked to that of the nearby mission town of Sonoma. Prior to the establishment in 1823 of a Franciscan mission in Sonoma, the area north of San Francisco was largely unsettled. California was at that time under Mexican jurisdiction and few if any pioneers braved the dangers posed by local Indian tribes, bears and the threat of attack by Russian soldiers camped along the Sonoma coast at Fort Ross and Bodega Bay.
Official County Map, 1895
Mission San Francisco Solano at Sonoma was the last of the twenty-one California missions to be built, located at the northern end of the Camino Real (royal highway). Each mission was charged with the task of converting the Indians to Christianity as well as overseeing all land surrounding the mission.
By pushing the northern edge of the frontier as far as Sonoma, the missionaries paved the way for the future development of Sonoma, Napa, and Mendocino counties. By 1832, outposts had been established in Napa, Suisun, Santa Rosa, and Petaluma.
In 1834 the Mexican government moved to secularize all California missions. Mariano Guadalupe Vallejo, Military Commander and Director of Colonization of the Northern Frontier, arrived in Sonoma, along with ten families of would-be settlers, to take charge of the mission, free the Indians and distribute the mission lands. Under Vallejo's jurisdiction, hundreds of thousands of acres of land were freely granted to individuals meeting two criteria: proof of naturalized Mexican citizenship and a willingness to survey and develop the land.
In practice in the land grants were awarded almost exclusively to Vallejo's relatives or friends. The Carneros region lies principally within the original boundaries of four such land grants: Rincon de los Carneros, Entre Napa, Huichica, and Petaluma.
The first two and smaller of these three grants were made in 1836 to Nicholas Higuerra, while the third was awarded in 1841 and 1846 to Jacob P. Leese, a son-in-law of Vallejo. Leese's grant, Huichica, consisted of over 18,000 acres and comprises a large part of the Carneros region. Rincon de los Carneros - the namesake of the Carneros region - was one of the smaller grants, measuring approximately 2,500 acres. The Petaluma grant which forms the western portion of Carneros was granted to Vallejo by his superiors. Many portions of the grants were quickly subdivided and sold for farmland, speeding the process of the settling of Carneros.