The Ohlone people began in disappear at the same time that European Man invaded the area. The first were Spanish seeking gold and converts to Christianity. Later settlers came from the east coast of America to tame the wild west and seek their fortune. This culminated in the 1849 gold rush creating a vast migration of settlers to California. There was a great demand for lumber and the Santa Cruz mountains had vast redwood forests to supply it. By 1884 there were 28 lumber mills providing an annual yield of over 34,000,000 board feet of lumber.
By the early 1900's, Castle Rock had become somewhat of a tourist attraction. An interurban streetcar carried people from the Santa Clara Valley to Congress Springs, just west of Saratoga. From there visitors could either hike or hire a rig to take them up to Castle Rock. One of the more frequent visitors to Castle Rock in those days was a young man by the name of Russell Varian.
Russell Varian hiked and explored the rugged, yet beautiful, Castle Rock area while still a boy. As an adult, he laid the groundwork that would eventually make Castle Rock a state park. His dream was to preserve the land around Castle Rock as a public park for all to enjoy. When the State showed little interest in purchasing the land, Russell took the initiative and decided to purchase the land himself and then donate it to the state. In 1959 he obtained an option to buy the land but unfortunately, died before the actual purchase could be completed.
Russell Varian's dream nevertheless began to come true that same year when memorial funds donated by his friends and associates secured the first 27 acres for the park. On July 12, 1968, the State Park and Recreation Commission officially designated Castle Rock as a State Park and opened the park with 513 acres. Today, Castle Rock State Park encompasses over 3,600 acres of semi-wilderness.