“It’s popular in the South and West, but it’s still only growing in the Northeast,” said Lawrence Hamm, chairman of the community activist group People’s Organization for Progress and the event’s keynote speaker. “This is a special day because it focuses specifically on slavery and emancipation. You really can’t understand current conditions in America unless you understand those two things.”

Hamm added this year’s celebrations were particularly momentous because the U.S. Senate issued an apology for slavery last week.

President Barack Obama also noted Juneteenth in a press release.

“June 19, or Juneteenth, is now observed in 31 states,” Obama said. “Nearly a century and a half later, the descendants of slaves and slave owners can commemorate the day together and celebrate the rights and freedoms we all share in this great nation that we all love.”