Marijuana—also known as marihuana or cannabis—is classified as a controlled substance under federal law, and its possession, use, and distribution is illegal. See 21 U.S.C. §812.

But many states have recently passed laws that generally legalize marijuana in some form. For example, Alaska, California, Colorado, Illinois, Maine, Massachusetts, Michigan, Nevada, Oregon, Vermont, and Washington have enacted laws legalizing marijuana for recreational use.

The District of Columbia allows all citizens over the age of 21 to possess up to two ounces of marijuana, to use and grow marijuana on private property, and to exchange marijuana between persons as long as no money, goods, or services are exchanged.

And some states that do not allow recreational use of marijuana do allow limited use of marijuana to treat symptoms of illness and other conditions—known as medical marijuana. States that allow limited use of medical marijuana include Arkansas, Arizona, Connecticut, Delaware, Florida, Hawaii, Louisiana, Maryland, Massachusetts, Minnesota, Missouri, Montana, New Hampshire, New Jersey, New Mexico, New York, North Dakota, Ohio, Oklahoma, Pennsylvania, Rhode Island, Utah, Vermont, and West Virginia. The medical marijuana laws in some of these states are broader than others, with some states only allowing use of cannabis-infused products such as oils and pills. Federal law prohibits health care practitioners from writing a prescription for medical marijuana, so practitioners in medical marijuana states write a recommendation for medical marijuana.

Other states have not legalized marijuana, but have decriminalized it—meaning possession of small amounts of marijuana is not punishable by jail or prison time, but may be punished with a fine. States that have decriminalized possession of marijuana under limited circumstances include Connecticut, Maryland, Mississippi, Nebraska, New Hampshire, New Mexico, New York, North Carolina, and Virginia.

Marijuana laws are generally located in a state’s statutes—often in the penal or criminal code, or in the health and safety code.

In South Dakota, as of the knowledge cutoff in early 2023, marijuana remains illegal for recreational use under state law. However, South Dakota has passed measures to allow medical marijuana following the approval of Initiated Measure 26 in the November 2020 election. This measure allows patients with debilitating medical conditions to possess and use marijuana for medical purposes, as recommended by a physician. Despite the state-level legalization of medical marijuana, it is important to note that under federal law, specifically 21 U.S.C. §812, marijuana is still classified as a Schedule I controlled substance, and its possession, use, and distribution are illegal. This creates a conflict between federal and state law where state laws allow marijuana use. Additionally, South Dakota has not decriminalized marijuana, meaning that possession of small amounts can still result in criminal penalties. It is essential for individuals in South Dakota to be aware of both state and federal laws regarding marijuana to understand the potential legal consequences.