(ABC4) – On June 19, 1865, slaves in Galveston, Texas, learned they were free – two and a half years after President Abraham Lincoln signed the Emancipation Proclamation.

Nearly 156 years later, President Joe Biden signed a law establishing June 19 as Juneteenth National Independence Day, commemorating the end of slavery in the U.S. Juneteenth is now the 12th federal holiday, and the first since Martin Luther King Jr. Day was created in 1983.

While it has just become a national holiday, it is the oldest nationally celebrated commemoration of the end of slavery in the U.S., according to Juneteenth.com.

You may see a flag, like the one below, during Juneteenth celebrations. But what does it mean?

The Juneteenth flag flies in Omaha, Neb., Wednesday, June 17, 2020. The Juneteenth flag commemorating the day that slavery ended in the U.S. will fly over the Wisconsin Capitol for the first time in state’s history, Gov. Tony Evers announced Wednesday. (AP Photo/Nati Harnik)

According to California State University Long Beach, the first flag representing Juneteenth was created in 1997 by Ben Haith, the founder of the National Juneteenth Celebration Foundation.

As you can see, the flag is comprised of a red and blue stripe (with the red strip arcing), a ‘burst’, a star, and in some cases, the date June 19, 1865.

Here is what each aspect means, according to CSU and the National Juneteenth Celebration Foundation:

The colors: In addition to the red and blue stripe, the color white is seen in the burst and the star. The use of these three colors serves as a reminder that enslaved people and their descendants were and are Americans.

The star: It represents two things – Texas, the Lone Star State, and the freedom of Black Americans nationwide.

The burst: The outline around the star is inspired by a nova, a new star, that reflects a new beginning.

The arc: The curve between the colored stripes is meant to represent a new horizon.

The date: In 2007, the date was added to the flag as a reminder of the historic day in 1865.

Locally, Salt Lake County Mayor Jenny Wilson and Salt Lake City Mayor Erin Mendenhall will raise the Juneteenth flag on Friday to commemorate the day.