San Lorenzo is officially known as San Lorenzo Village, and is a census-designated place in the Northern California county of Alameda. It is the ancestral home of the Chochenya indigenous people. The village is located on the route of El Camino Viejo, on the land of the former Rancho San Lorenzo, a Mexican land grant given to Guillermo Castro in 1841.
Early settlers during the California Gold Rush era lived as squatters on the Rancho San Lorenzo, and the informal name given to the area was Squattersville. The shop, a blacksmith repair shop for wagons and farm equipment, was the first official business to open its doors in the town in 1853, and was an essential part of the community. It remained in business until the 1930s, when wagons and independent blacksmithing had by and large become unnecessary.
The first post office opened in San Lorenzo in 1854.