The property rights for Montaña de Oro State Park land area changed hands several times after California became a territory of the United States. Part of the park was the Rancho Cañada de los Osos that Victor Linares had been granted on December 1, 1842 by Governor Juan B. Alvarado. The rancho lay west of San Luis Obispo in the Los Osos Valley. Victor Linares sold his rancho to James Scott and John Wilson who also bought the adjacent Rancho Pecho y Islay in the Irish Hills to the south of their Los Osos rancho and combined them in a new 32,431 acre grant, Rancho Cañada de los Osos y Pecho y Islay from Governor Pio Pico in 1845.