Origins of the Park
The Ohlone people were the first inhabitants of the area that is currently known as Castle Rock State Park. They lived mostly in the river valleys, as they believed the redwood groves to be sacred. The Ohlone often traversed the park on their way to and from the sea or from one harvest to another. The few remnants of tools and artifacts show that they hunted and fished in these lands for hundreds of years. Within a few generations, their way of life disappeared, and was replaced by Europeans, many of whom were simply looking for land fortune, or gold.

Lumber Mills
In 1880 the South Pacific Coast Railroad was completed between Santa Cruz and Alameda. This led to more than twenty-five lumber mills operating in the Big Basin/San Lorenzo Valley Area alone. Most families were also involved in farming, hunting, and fishing. In 1886 the first school was opened with six students. The first teacher, Miss Ida M. Jones, actually lived in a cave for about six weeks until a cabin could be built for her.

Conservation Efforts
During this era, Judge J.D. Welch, an early conservationist, acquired Castle Rock and much of the land surrounding it. By the early 1900's, an interurban streetcar ran between Santa Clara and Congress Springs, just west of Saratoga, where visitors could hire a rig to take them up to Castle Rock. One frequent visitor in those days was Russell Varian, who was destined to become a famous scientist and the park's founder. His goal was to secure the park for the future, and in 1959 he obtained an option to buy the land through the Sierra Club. Although he died shortly before the purchase could be completed, his dream became reality when his memorial fund secured the first twenty-seven acres. On July 12, 1968, Castle Rock State Park officially opened with 513 acres of land donated by the Varian Foundation and the Sierra Club.