The bill, which was passed overwhelmingly by the U.S. House of Representatives on Wednesday after clearing the Senate unanimously, marks the day in 1865 when a Union general informed a group of enslaved people in Texas that they had been made free two years earlier by President Abraham Lincoln's Emancipation Proclamation during the Civil War.

"Juneteenth marks both a long hard night of slavery subjugation and a promise of a brighter morning to come," Biden said. The day is a reminder of the "terrible toll that slavery took on the country and continues to take."

European colonists first forcibly brought enslaved Africans by ship to the British colonies that became the United States in the 1600s; millions of people were legally owned there until the 13th Amendment passed in 1865.

"Great nations don't ignore their most painful moments...they embrace them," Biden told a room filled with about 80 members of Congress, community leaders and activists including 94-year-old Opal Lee, who campaigned for decades to make Juneteenth a federal holiday.

Vice President Harris reminded the White House guests that they were gathered in a "house built by enslaved people," and said the holiday would be an occasion to "reaffirm and rededicate ourselves to action."

Juneteenth will be the eleventh federally recognized holiday, and the first in nearly four decades, following one honoring slain civil rights leader Martin Luther King, Jr.

Federal employees will start taking the holiday off this year, observing it on Friday since Juneteenth falls on Saturday, the U.S. Office of Personnel Management said on Twitter.

SERIOUS INEQUALITY REMAINS

Biden and his fellow Democrats are under pressure to respond to a slew of Republican-backed state bills that civil rights activists say aim to suppress voting by minorities, and to meaningfully address the disproportionate killing of Black men by police.

Some Republicans are also pushing state bills that discourage history teachers from focusing on the U.S.'s history of slavery and racism.

Many Republicans backed the Juneteenth bill in Congress; several of the over a dozen who opposed it said declaring a "Juneteenth National Independence Day" would needlessly divide or confuse Americans.

While celebrities and federal officials cheered the holiday's creation, some questioned whether it would have real impact on the country's deep-seated issues.

"It's important to commemorate emancipation and to encourage everyday Americans to reckon with the history of slavery ... but there is always a danger with these sort of things so they can be performative," said Matthew Delmont, a professor of history at Dartmouth College who specializes in African-American history and civil rights.

Designating Juneteenth a federal holiday will be a "failure" if it just acknowledges the date without spurring action on issues such as police brutality, voting rights, and the racial wealth gap, Delmont said.

The law comes a year after the United States was rocked by protests against racism and policing following the murder of George Floyd, an African-American man, by a Minneapolis police officer.

Biden said the administration has launched an "aggressive effort" to fight racial discrimination in housing, drive Black home ownership and offer resources to historically Black colleges and universities (HBCUs).

“The promise for equality is not going to be fulfilled until it becomes real in our schools, on our main streets and in our neighborhoods,” he said.