St. Louis County Insane Asylum (Former)

A hilltop asylum built for 300 patients that became an overcrowded institution—and still survives in altered form.

The Former St. Louis County Insane Asylum

The historic Dome Building on Arsenal Street began as the St. Louis County Insane Asylum in 1869, a public institution whose history mirrors changing ideas about mental illness, treatment and confinement.

The Story

The St. Louis County Insane Asylum opened on April 23, 1869, with 300 beds. Its hilltop setting and monumental domed building reflected nineteenth-century faith that ordered surroundings and specialized institutions could help treat mental illness.

After St. Louis separated from the county in 1876, the institution became the St. Louis City Insane Asylum. Overcrowding eventually overwhelmed its therapeutic ambitions. By the turn of the twentieth century, patient numbers far exceeded capacity and the institution increasingly provided custodial rather than curative care.

The campus continued through multiple names and eras of psychiatric treatment. The surviving Dome Building remains a striking physical link to more than 150 years of mental-health history.

What Remains Today

The historic Dome Building survives on the modern state psychiatric campus associated with the St. Louis Forensic Treatment Center. It is not an abandoned attraction and remains part of an institutional site.

Visiting Information

Do not enter the psychiatric campus or historic buildings without authorization. The site should be treated as an active healthcare and state facility; exterior observation must respect access restrictions and patient privacy.