The Federal Comprehensive Drug Abuse Prevention and Control Act of 1970 (the Controlled Substances Act) made the use and possession of cannabis illegal under federal law.

A major change to the legal status of cannabis occurred with the passage of the Agriculture Improvement Act of 2018, commonly referred to as the 2018 Farm Bill. Although hemp and marijuana are both varieties of the Cannabis sativa plant, the 2018 statute differentiated hemp from marijuana based on chemical composition—specifically the amount of tetrahydrocannabinol (THC) present in the sample.¹