Rancho Santa Rosa was a 15,526-acre (62.83 km2) Mexican land grant in present day Santa Barbara County, California one and half square leagues given in 1839 by Governor Pro-tem Manuel Jimeno, and two additional square leagues given in 1845 by Governor Pío Pico to Francisco Cota.[1] The grant in the Santa Ynez Valley extended along both banks of the Santa Ynez River at Santa Rosa Creek, west of present day Buellton.[2][3]
Francisco Atanasio Cota (1787–1851) was a soldier at the Presidio of Santa Barbara. In 1811, he married María de Jesus Olivera (1791–1877). He was administrator at Mission Santa Inés 1837-1841.
With the cession of California to the United States following the Mexican-American War, the 1848 Treaty of Guadalupe Hidalgo provided that the land grants would be honored. As required by the Land Act of 1851, a claim for Rancho Santa Rosa was filed with the Public Land Commission in 1852,[4][5] and the grant was patented to María Jesús Olivera de Cota in 1872.[6]
Joseph W. Cooper[7] bought Rancho Santa Rosa in 1868.[8]