On June 13, 1894, the first wards were accepted at the Preston School of Industry, and the school was proclaimed officially opened on July 1, 1894. The next year, electricity was installed by way of a water wheel powered dynamo, called a Pelton Wheel, for incandescent and arc lights.
The Preston School of Industry remained open until 1960 when new facilities for the school were completed. The building remained vacant and fading into disrepair until September 10, 2001 when The Preston Castle Foundation received a fifty-year lease for the property. The Preston Castle has also been named a California State Historical Landmark (#867) and is listed on the National Register of Historic Places (NPS-75000422).