When the United States took possession of California and other Mexican lands in 1848, it was bound by the Treaty of Guadalupe Hidalgo to honor the legitimate land claims of Mexican citizens residing in those captured territories. The land upon which the former Camarillo State Hospital sat, once belonged to Isabel Yorba as part of an 1836 land grant, known as "Rancho Guadalasca."[2]
In 1929, the California legislature initially appropriated $1,000,000 for the purchase of land and buildings to be utilized for a state hospital. Three years later, 1500 acres of the 8600 acre Lewis Ranch, owned by agriculturists Joseph P. Lewis and Adolfo Camarillo, located within the City of Camarillo, County of Ventura was acquired for $415,000.[2]
Architectural plans for the new hospital were rushed to state architect, George McDougall, to begin the process to accommodate the initial 3000 patients for the first unit. The hospital was expected to cover 200 acres with supply wards, homes for the superintendent and officials, dormitories for employees and patients, commissaries, and storerooms. It was anticipated that the completed hospital would house 7000 patients and over 700 staff
