New York Governor Andrew Cuomo is due to announce an executive order on Wednesday paving the way for New York to become the 21st U.S. state, along with the District of Columbia, to allow medical marijuana.
Marijuana remains illegal under federal law, though the U.S. Department of Justice says it will not interfere with states' efforts to regulate and tax marijuana provided they are able to meet a set of requirements including keeping it from children and restricting its flow into other states.
Following are details on marijuana laws in different states, with information provided by the National Conference of State Legislatures and the Marijuana Policy Project:
Washington state and Colorado voters decriminalized recreational use of marijuana in 2012. Colorado's recreational-use stores opened January 1 and similar establishments will not open in Washington until later this year. Both states have set up rules for growers, processors, retail sellers and testers of the drug.
Advocates of legalization have vowed to get the recreational use issue on the ballot in several more states by 2016, including California, Alaska, Arizona and Oregon.
California voters in 1996 passed Proposition 215, making it the first state to allow for the medical use of marijuana.
Nineteen more states, along with Washington, D.C., have since enacted similar laws, including five since 2011.
Depending on the state, patients can grow their own pot, obtain it from a dispensary, or both. With New York Governor Andrew Cuomo's executive order allowing some hospitals to dispense marijuana, the Empire State will become the 21st to allow medical pot use.
Fifteen states, among them Hawaii, Montana and Maine, allow at least some patients to grow limited quantities of marijuana for themselves.
While most states place few restrictions on which patients are allowed to cultivate the drug, Arizona requires them to live at least 25 miles from a dispensary and Massachusetts limits it to those physically, financially or geographically encumbered from buying from a dispensary.
Fifteen states and Washington, D.C., have passed laws permitting medical pot dispensaries, from which patients can obtain the drug.
In seven of those states, including Connecticut, Illinois and New Hampshire, those laws are due to take effect by 2015.
Three other states - Montana, Michigan and Washington state - have dispensaries operating within their borders that are not explicitly authorized by the state. Some dispensaries grow their own pot, while others get it from state-licensed growers or from patients.
(Reporting by Jonathan Kaminsky; Editing by Edith Honan and Stephen Powell)