Twenty states and the District of Columbia now have laws legalizing marijuana in some form.
So far, only Colorado and Washington state have legalized marijuana for recreational use, while other states permit medical marijuana.
A limited medical marijuana law most recently went into effect Oct. 1 in Maryland, allowing authorized academic medical centers and research centers to distribute it. However, patients are not expected to be able to sign up for the program until 2015.
Illinois legalized medical marijuana with a law establishing a pilot program set to be implemented in January.
The map below show states permitting marijuana use for medical and recreational purposes.
Information below is current as of December 2013 and includes ballot measures approved in the 2012 elections that have yet to take effect: