Primarily a spread-out residential area in western Thousand Oaks, Newbury Park is a scenic area home to many parks and trailheads. Shops, restaurants, and fast-food eateries are gathered along the Ventura Freeway, while the Stagecoach Inn Museum is housed in a 19th-century hotel replica. Hiking paths among lush rolling hills and a cultural center are highlights of picturesque Rancho Sierra Vista/Satwiwa park.
Timberville was the 19th-century name for Newbury Park. Newbury Park is named after Egbert Starr Newbury, the founder of Newbury Park, who was also the first postmaster in the Conejo Valley in 1875. Egbert Starr Newbury called his ranch “Newbury Park”, which became the name for the entire town. The Newbury Park Post Office has changed locations numerous times but the Newbury Park name has survived and is still used even though much of the area was incorporated into the city of Thousand Oaks.
The History of Newbury Park is believed to have been inhabited by people of the Chumash culture for at least the past 10,000 years. Newbury Park has been home of three Chumash villages: Satwiwa by the southern edge of town, as well as two villages that were located by today’s Ventu Park Road. These villages were settled 2,000 years ago and had a population of 100–200 inhabitants in each village. In addition to those three, a large Chumash village was located just north of Arroyo Conejo Open Space by Wildwood Regional Park. Other nearby villages include Lalimanux (Lalimanuc or Lalimanuh) at the base of the Conejo Grade by westernmost Newbury Park, as well as Kayɨwɨš also by the Conejo Grade


In the 19th Century E.S. Newbury, Howard Mills, and John Edwards were among the first to buy former Rancho El Conejo land in the early 1870s. El Rancho Conejo was an area which today encompasses most of the Conejo Valley and was named for its many rabbits. Its name derives from a Spanish land grant in California, encouraged by the Spanish- and Mexican governments.
Modern Newbury Park was a more established and older community than Thousand Oaks at the beginning of the 20th century.
In the early 20th century, Newbury Park had a few ranches and stores, wedged between Borchard lands to the south and Friedrich land on the north. During the 1940s, Ventu Park behind Newbury Park’s main street became a 500-acre real estate development. Lots sold to movie stars and others seeking a rustic retreat. One of the male members of the New YorkRothschilds built a large home by Ventu Park and lived in relative seclusion here in the 1940s.
Prior to the 1960s, Newbury Park was never incorporated as its own city or municipality, it was unincorporated areas of Ventura County with little development. During the 1950s there were speculations persisting that Ventura County officials refused to allow Newbury Park to expand because of a feud with the would-be developers. Between 1950 and 1970, the Conejo Valley experienced a population boom, and increased its population from 3,000 to 30,000.
Many Newbury Park residents did not want to be part of Thousand Oaks, and many residents fought to stop the incorporation in fear of losing the Newbury Park identity. Newbury Park had made failed attempts at creating its own municipality in the early 1960s, not only to create its own city, but to also remain independent of Thousand Oaks.
A 1963 attempt at a cityhood election failed when the Janss’s Rancho Conejo Industrial Park and the Talley Corporation refused to join the efforts. Activist Reba Hays Jeffries of the Stagecoach Inn had a different explanation for interviewers when addressing why efforts at an independent municipality failed. She claimed the cityhood supporters were required to collect signatures from owners who represented 29% of the land area in Newbury Park.
As the efforts collected signatures from 29% of registered voters, and not Newbury Park landowners, the petition never appeared on the ballot. Reba M.H. Jeffries was one of several opponents to the idea of annexation when it was first proposed in 1967. Jeffries feared for the identity of Newbury Park and was quoted in an interview saying: “It’s a shame that the Thousand Oaks personality is overpowering to the extent that Newbury Park is losing its large ranches and freedom.” Jeffries was also opposed to the proposition to demolish the Stagecoach Inn in 1964 and fought to keep the Newbury Park Post Office in town.


The City of Thousand Oaks was formally established on September 29, 1964, and throughout the late 1960s and throughout the 1970s, most Newbury Park land was annexed by the City of Thousand Oaks. The annexed area was formerly controlled by Ventura County, but as of 2016, all but Casa Conejo and Ventu Park is within Thousand Oaks city limits. Together with Thousand Oaks, Newbury Park was part of a master planned community by the Janss Investment Company.
Newbury Park has had an increasing population due to the presence of biotechnology firms and technology corporations, such as Amgen (world headquarters) and Baxter, and other high-technology corporations.