There are 23 states that allow dispensing of marijuana for medicinal purposes as of August 2015, according to the National Conference of State Legislatures. Initially, California's Proposition 215 made it the only state to legalize medical marijuana use. Since that decision in 1996, 22 other states and the District of Columbia have passed similar legislation.
Medical marijuana dispensaries serve Arizona, California, Colorado, Connecticut and Delaware, notes the NCSL. Dispensaries also operate in Illinois, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New Mexico, Rhode Island, Washington and Vermont. In some states, dispensaries are allowed to operate but only offer limited products. For example, in New York, dispensaries may not sell products for smoking, and ingested products must contain no more than 10 milligrams of THC. In Minnesota, dispensaries can sell only liquid extracts. In Michigan, the state doesn't sanction dispensaries but allows local laws to determine if they are allowed in specific areas.