Yearly on June 19
Juneteenth is the oldest known celebration commemorating the ending of slavery in the United States. President Abraham Lincoln signed the Emancipation Proclamation, freeing slaves effective January of 1863.
But it wasn't until two years later, on June 19, 1865, when Union soldiers landed in Galveston, Texas, with news that the war had ended and that the enslaved were now free. After this, more than 250,000 slaves across Texas learned that they were finally free.
The celebration of June 19 was coined "Juneteenth" and grew with more participation from descendants as they treated the day as their Independence Day, according to the Texas State Library. It spread to other states and has been celebrated every year since.