The hook
A 120-room Romanesque castle rises over the Gold Country town of Ione — built in 1894 not as a mansion but as a reform school, and abandoned with a reputation dark enough that ghost-hunting TV keeps coming back.
01Why it's worth it
The Preston School of Industry opened in 1894 when seven boys were transferred here from San Quentin, and the state deliberately gave it the look of a school rather than a prison: 46,000 square feet of turrets and arches, the finest example of Romanesque Revival architecture in the Mother Lode. The reality inside was harsh — lashings, isolation, military drill — and that grim history, plus decades of decay after it closed in 1960, is why the castle has become a fixture of paranormal television (Ghost Adventures, Ghost Hunters). A local foundation saved it from ruin, now owns it, and runs the only legitimate way in: guided historic tours and, in season, paranormal nights. It's a genuinely imposing, genuinely unsettling building most Bay Area day-trippers have never heard of, an easy add to a Gold Country loop.
02How to experience it
Palm Drive, Ione (Amador County). Access is guided-only — the foundation runs historic tours on the first and third Saturdays April through August, with paranormal tours seasonally (prestoncastle.org; book ahead). Pairs with Sutter Creek and the Amador wineries, or Volcano's tiny historic main street.