The history of Thousand Oaks is rooted in the deep past, long before European settlers arrived. Originally, these lands were home to the Chumash tribe, who lived here for thousands of years. Evidence of their culture and way of life is still found in the region. Europeans first appeared here in the 16th century with the expedition of Juan Rodríguez Cabrillo, but active development began much later. The area got its name from the numerous oak groves that still define its landscape today.
A key moment in the formation of the modern city was the mid-20th century. Before then, the territory was used primarily for cattle ranching and agriculture. In the 1950s, the large development firm Janss Investment Company purchased a massive ranch of about 10,000 acres (approximately 40 sq km) to create a carefully planned city from scratch. It was this project that laid the foundation for modern Thousand Oaks, which officially received city status in 1964. A major development factor was the construction of the Ventura Freeway (U.S. Route 101), which connected the isolated Conejo Valley to Los Angeles and other major Southern California centers.
From the beginning, Thousand Oaks developed not as a typical suburb, but as a "park city." The economy, originally agrarian, transformed rapidly, with the primary focus on creating a comfortable residential environment with a high quality of life. The master plan concept envisioned preserving large tracts of open space, parks, and green zones. The city's cultural identity was formed around the idea of harmonious coexistence with nature, which remains one of its main distinguishing features today.