| Part of the Hippie movement | |
 An Acid Test handbill | |
| Date | 1965–1966 |
|---|---|
| Location | California, Texas |
| Part of a series on |
| Psychedelia |
|---|
 |
The Acid Tests were a series of parties held by author Ken Kesey primarily in the San Francisco Bay Area during the mid-1960s, centered on the use of and advocacy for the psychedelic drug LSD, commonly known as "acid". LSD was not made illegal in California until October 6, 1966. Under Governor Ronald Reagan’s administration.