The Democrat-led House of Representatives has voted to make June 19, also known as Juneteenth, a federal holiday commemorating the end of slavery in the US.
Wedneaday's 415-14 vote in the lower chamber to pass the legislation came one day after the Senate approved the bill with unanimous consent, reports Xinhua news agency.
It now goes to President Joe Biden's desk to be signed into law.
"What I see here today is racial divide crumbling, being crushed this day under a momentous vote that brings together people who understand the value of freedom," Representative Sheila Jackson Lee, the Texas Democrat who sponsored the bill, said at a press conference prior to the vote.
"Juneteenth honours the end of the years of suffering and brutality that African Americans endured under slavery, America's original sin, and celebrates the legacy of perseverance that has become the hallmark of the African-American experience in the struggle for equality."
Celebrated on June 19, Juneteenth commemorates the last remaining enslaved African-Americans in Galveston, Texas, being emancipated by Union Army on that day in 1865.
The announcement by Union Army General Gordon Granger that the enslaved people were free came more than two years after then President Abraham Lincoln issued the Emancipation Proclamation.
All of the 14 "No" votes on Wednesday were cast by Republicans, some of whom argued that officially designating the Juneteenth National Independence Day could lead to confusion, making it difficult to differentiate the new holiday from Independence Day on July 4.
"Why not be named the Juneteenth National Emancipation Day," said Republican Representative Clay Higgins of Louisiana, who voted in favour of the bill but argued the legislation was used by Democrats as "a trap for conservatives".
Other dissenters claimed that the bill was part of Democrats' effort to crush conservative ideologies in the country by means of a culture war.
"This is an effort by the left to create a day out of whole cloth to celebrate identity politics as part of its larger efforts to make Critical Race Theory the reigning ideology of our country," Republican Representative Matthew Rosendale of Montana said in a statement before casting the 'no' vote.
If the legislation becomes law, Juneteenth would become the 11th annual national holiday on the federal calendar.
It is already recognised by 47 states and the District of Columbia as an official holiday or observance.