The movement to decriminalize psilocybin in the United States began in 2019 with Denver, Colorado, becoming the first city to decriminalize psilocybin in May of that year. The cities of Oakland and Santa Cruz, California, decriminalized psilocybin in June 2019 and January 2020, respectively. Washington, D.C., followed soon in November 2020, as did Somerville, Massachusetts, in January 2021, and then the neighboring Cambridge and Northampton in February 2021 and March 2021, respectively. Seattle, Washington, became the largest U.S. city on the growing list in October 2021. Detroit, Michigan, followed in November 2021.
Oregon voters passed a 2020 ballot measure making it the first state to both decriminalize psilocybin and also legalize its supervised use.[1][2] Colorado followed with a similar measure in 2022.[3] The use, sale, and possession of psilocybin in the United States is illegal under federal law.