Oregon is set to become the latest US state where recreational cannabis can be bought legally.
The rules coming into force on Thursday will enable residents aged over 21 in the north-western state - known as the bohemian capital of the US - to buy up to a quarter-once (7g) of dried pot.
Customers will be able to pick up cannabis from the state’s 200 existing medical marijuana dispensaries.
For now, sales of marijuana will be untaxed, but that is expected to change in the New Year.
Stores in Oregon have attempted to attract customers by extending their hours, giving away food and cutting the price of marijuana.
Eager buyers queued outside the Shango medical marijuana dispensary near Portland International Airport to buy the drug at midnight when the changes come into effect.
Co-founder Shane McKee told the Associated Press: “It looks like there is about 60-70 in line out front.”
The store’s first buyer Davia Fleming said the sales launch was important.
"It's the end of a prohibition," he said.
She described the atmosphere inside the store as "beautiful. ... very friendly; everyone is upbeat."
Juliano Hamana, 24, who was queuing with his girlfriend, told Reuters: "We came to be part of the experiment,"
"I'm worried about the 25 percent tax coming in January," he said, "but for a $10 gram that's only a bit over $2 more. I think it might be worth it for the quality."
Residents of Oregon and Alaska voted to legalise marijuana use and possession last year, bringing those states in line with Washington State and Colorado.
Dedicated recreational cannabis stores like those in Washington state and Colorado are expected to open in Oregon and Alaska in 2016.
Cannabis around the world
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Marijuana possession has also been legalised in Washington DC, while Ohio and other states will vote on the topic in November.
Those in favour of legalisation believe the law will hit the black market, but others are concerned that it may make it easier for children to access the drug.
Around 30 municiplaities in Oregon have already banned or sharply limited the sale of recreational pot.
In Portland, the state's largest city, politicians approved rules limiting where recreational marijuana stores can open, and have made it illegal to open a store closer than 1,000 feet (305 meters) from a school.Reuse content