Weston State Hospital was a large mental health institution in Lewis County that operated from 1864 to 1994. It once housed more than 1,000 patients.

The hospital had a huge main building, its own farm, and a cemetery. It was used for treatment for many years, though some practices used there are now considered harmful.

After closing in 1994, the building became a historic site and tourist attraction known as the Trans-Allegheny Lunatic Asylum (the original name when it opened in 1864).