Mission Santa Cruz was established in 1791, twelfth of the twenty-one Spanish Missions of California. After first trying to build near the San Lorenzo River, winter flooding convinced the padres to move up onto the bluff known ever since as Mission Hill. The low-lying river bottom north of the hill where mission buildings were constructed became the potrero, a protected pasture area where livestock other than free-ranging cattle were kept. The potrero was a relatively small flat area enclosed between steep hills and the river. In 1834, the missions were secularized and, over the following years, most of the former mission lands were given away by the Alta California government as large land grants called ranchos. A rectangular portion of the former potrero land was granted in 1842 to Jose Arana, one of a group of colonists who came to Alta California from Mexico in 1834. Arana later moved to the Rancho Arroyo del Rodeo, a few miles to the east. The creek running through his former lands there is now called Arana Gulch. The rancho passed into the hands of pioneer Isaac Graham. In gratitude for his help during what came to be known as "The Graham Affair", Graham gave the tract to Thomas J. Farnham after Graham's return to the Santa Cruz area in 1841. Farnham died in San Francisco, in 1848, without ever taking possession of the land, but his widow Eliza moved west from New York the following year and decided to remain. Renaming the tract El Rancho La Libertad, Eliza Farnham attempted to establish a farm and build a house. When that proved unsuccessful, she sold the land to Thomas Russell, who operated a distillery in the hills above. Russell filed a petition in 1855 to patent the original Mexican grant through the Public Land Commission. Russell's diseño, shows the rancho lands on either side of a creek identified as "Arroyo de San Pedro Regalado". That spring-fed, year-round creek is known today as Pogonip Creek. Four structures are identified: three "casas" and a "Molino". The San Lorenzo River is identified as the "Rio de Sta. Cruz". Only a year later, Thomas Russell was murdered in a case that was never solved, and the land passed to his son Alexander before the grant was finally patented in 1859. Alexander was apparently still in possession of at least part of the rancho when the first complete map of Santa Cruz Countyland ownership was published in 1889 - the name "Russell" appears on the map in the potrero area.
