The District of Columbia City Council on March 4 voted to remove criminal penalties for the possession of marijuana in amounts of one ounce or less.
The bill would treat such possession as a civil offense.
It still needs the approval of Mayor Vincent Gray and then Congress.
The council vote was 10 to 1, with one abstention.
"This vote is proof: The people of Washington, DC, are tired of living in a city where a Black person is eight times more likely to be arrested for marijuana possession than a white person, despite similar rates of use," said Seema Sadanandan of the ACLU. "This legislation is a victory for racial justice — a crucial step towards eliminating racial profiling in the enforcement of drug laws and the disproportionate punishments suffered by people of color in this city."
Last year, the ACLU released a report showing the the severe racial disparities in arrests in the district for marijuana possession.
Ezekiel Edwards, director of the ACLU's Criminal Law Reform Project, said, "With its decriminalization bill, Washington, D.C., joins the ever-growing number of cities and states enacting marijuana reform. We look forward to the day when the whole country has rejected marijuana prohibition and the unfair burdens it places on people of color."
The bill, titled the Marijuana Possession Decriminalization Amendment Act of 2014, would allow police to fine a person $25 for possessing an ounce or less of marijuana, while also requiring forfeiture of the marijuana and any paraphernalia connected to personal consumption or transport.