The United States is gradually becoming the land of the red, white, and green.
Nine states and Washington, DC, have legalized marijuana for recreational use for adults over the age of 21. Medical marijuana is legal in another 30 states after voters in Oklahoma approved a ballot initiative to legalize medical marijuana in June.
Support for the drug reached new highs in 2018. A Gallup poll showed that 64% of Americans favor legalization, and even a majority of Republicans back it.
Legal marijuana sales exploded to $9.7 billion in North America in 2017, according to a report from Arcview Market Research and BDS Analytics. That represents a 33% increase over 2016, shattering previous expectations about how quickly the marijuana industry could grow in the face of federal prohibition. By 2022, Arcview expects global spending on legal cannabis to hit $32 billion by 2022, representing a 22% growth rate over the four-year period.
Here's a summary of where Americans can legally light up — no doctor's letter required — in 2018.
Adults 21 and over can light up in Alaska. In early 2015, the northernmost US state made it legal for residents to use, possess, and transport up to an ounce of marijuana — roughly a sandwich bag full — for recreational use. The first pot shop opened for business in late 2016.
Alaska has pounced on the opportunity to make its recreational pot shops a destination for tourists. More than two million people visit Alaska annually and spend $2 billion.
It was the first state to legalize medical marijuana back in 1996. California became even more pot-friendly in 2016 when it made it legal to use and carry up to an ounce of marijuana.
The law also permits adults 21 and over to buy up to eight grams of marijuana concentrates, which are found in edibles, and grow no more than six marijuana plants per household.
But not all Californians can legally smoke marijuana, depending on where they live. Many cities in the Central Valley, including Fresno and Bakersfield, have moved to ban recreational sales.
In Colorado, there are more marijuana dispensaries than Starbucks and McDonalds locations combined. The state joined Washington in becoming the first two states to fully legalize the drug in 2012.
Residents and tourists over the age of 21 can buy up to one ounce of marijuana or eight grams of concentrates. Some Colorado counties and cities have passed more restrictive laws.
A ballot initiative gave Mainers the right to possess up to 2.5 ounces of marijuana, more than double the limit in most other states. But that doesn't mean residents can buy the drug.
Lawmakers in Maine reached an agreement in May to make the legalization bill law, though Gov. Paul LePage remains an opponent of marijuana legalization. Marijuana dispensaries are expected to open within the state by 2019, The Portland Press Herald reports.
In 2016, Massachusetts gave residents the green light to carry and use an ounce of marijuana and grow up to 12 plants in their homes. But the future of the state's legal market is hazy.
Lawmakers delayed the opening of pot shops to July 2018, instead of the January 2018 date that voters approved in the election. Until then, there will be no sales of recreational weed.
Residents and tourists who are 21 and over can buy an ounce of marijuana or one-eighth of an ounce of edibles or concentrates in Nevada — while supplies last. Less than two weeks after sales of recreational weed began on July 1, 2017, many stores ran out of marijuana to sell.
The state has earned nearly $20 million in marijuana tax revenue since the market launched.
There's bad news if you want to grow your own bud, though. Nevada residents must live 25 miles outside the nearest dispensary in order to be eligible for a grower's license.
Oregonians have enjoyed the right to carry an ounce of weed and grow up to four plants at home since 2015. It's also legal to give edibles as a gift, as long as they're ingested in private.
Sales have exploded since legalization. In 2017, the state paid out $85 million in marijuana tax revenue to fund schools, public health initiatives, state police, and local government.
Vermont became the first state to legalize marijuana through the legislature, rather than a ballot initiative, when Republic Governor Phil Scott signed a bill into law on January 22.
Adults in the Green Mountain State will be able to carry up to an ounce of marijuana and grow no more than two plants for recreational use. The new law goes into effect in July. But the bill is limited in scope. It doesn't establish a legal market for the production and sale of the drug.
Dispensaries in Washington have raked in over $1 billion in non-medical marijuana sales since the drug was legalized for recreational use in 2012.
The state allows people to carry up to an ounce of marijuana, but they must require the drug for medicinal purposes in order to be eligible for a grower's license. So you can smoke it, but not grow it if you're toking for fun.
Residents in the nation's capital voted overwhelmingly to legalize nonmedical marijuana in November 2014.
The bill took effect in 2015, allowing people to possess two ounces or less of marijuana and "gift" up to an ounce, if neither money nor goods or services are exchanged.
Read next on Business Insider: This map shows every state that has legalized marijuana