Marijuana enthusiasts lit up their joints with confidence Thursday on the first full day of legal pot in the US capital, and looked forward to a day when all America might be able to follow suit.

Residents of Washington can now possess up to two ounces (56 grams) of marijuana -- enough to fill two sandwich bags -- and grow as many as six plants in the privacy of their homes without threat of arrest.

Head shops will be free to sell pot paraphernalia, but retail sales of marijuana remain prohibited -- and no cannabis will be tolerated on federal land, including the White House and Capitol grounds.

"It feels great. It feels like freedom," said Adam Eidinger, chairman of the DC Cannabis Campaign, as he rolled and lit up a joint at a press conference in the organization's crowded headquarters.

His group spearheaded the initiative that saw 69.4 percent of voters in Washington favoring legalization of small amounts of pot for personal use.

The capital city of 650,000 now follows Colorado, Washington state and Alaska in legalizing pot, with Oregon to follow in July.

"Something in the air today. Washington DC is smelling a lot like freedom," said NORML, National Organization for the Reform of Marijuana Laws, on its Twitter account.

But under federal law, marijuana remains not only illegal, but also classified as a "schedule one" substance on a par with heroin and LSD.

Possession can lead to a year in prison and a $1,000 fine for a first offense, going up to three years and $5,000 for repeat offenders.

Stiffer penalties loom for those convicted of selling and cultivating pot.

Federal prosecutors have been instructed, however, not to pursue minor cases in those states that have legalized pot.


'Huge step forward'

"What you're seeing here (in Washington) is the end of marijuana prohibition ... a huge step forward in the national fight for legalization," Michael Collins of the Drug Policy Alliance told the Washington Post.

Republicans lawmakers have threatened to overturn legalization, using a rarely-used power of Congress to meddle in municipal affairs in the District of Columbia, as the capital is formally known.

Jason Chaffetz, a conservative congressman from Utah, has warned of "very serious consequences" that could include jail time for city officials.

But Republican Mark Meadows, who chairs a House subcommittee that deals with Washington affairs, said "there's no talk of litigation" at this stage.

Pressing the pot issue risks igniting a debate over statehood for Washington, the only jurisdiction on the US mainland without a voting delegate in Congress.

Public opinion polls indicate that a slim majority of Americans favor legalization, and several states now allow doctor-prescribed medical marijuana to treat seriously ill patients.

By NORML's count, 31 states currently are considering marijuana law reform, making 2015 "one of the most active legislative sessions on record" for the legalization movement.

In Washington, Eidinger said what has been achieved so far "is not a hallelujah moment... What we really want ... is the right to be able to buy (marijuana) at a street corner in a store."