The legal history of cannabis in the United States relates to the regulation of cannabis (legal term marijuana) use for medical, recreational or industrial purposes in the United States. Increased restrictions and labeling of cannabis as a poison began in many states from 1906 onward, and outright prohibitions began in the 1920s. By the mid-1930s marijuana was regulated as a drug in every state, including 35 states that adopted the Uniform State Narcotic Drug Act. The first national regulation was the Marihuana Tax Act of 1937.
Multiple efforts to reschedule cannabis under the Act have failed, and the United States Supreme Court has ruled in United States v. Oakland Cannabis Buyers' Cooperative and Gonzales v. Raich that the federal government has a right to regulate and criminalize cannabis, even for medical purposes.
In 1619, King James I decreed that the American colonists of Jamestown would need to step up efforts to do their fair share towards supporting England. The Virginia Company enacted the decree, asking Jamestown's land owners to grow and export 100 hemp plants to help support England's cause. Later the colonists would grow it to support its expansion in the Americas.George Washington grew hemp at Mount Vernon as one of his three primary crops. The use of hemp for rope and fabric later became ubiquitous throughout the 18th and 19th centuries in the United States. Medicinal preparations of cannabis became available in American pharmacies in the 1850s following an introduction to its use in Western medicine by William O'Shaughnessy a decade earlier in 1839.