Juneteenth10th Annual Arts Festival in Cuyler Gore Park in Fort Greene, Brooklyn. Juneteenth is the oldest known celebration commemorating the ending of slavery in the United States. It was on June 19, 1865, that the Union soldiers, led by Major General Gordon Granger, landed at Galveston, Texas with news that the war had ended and that the enslaved were now free. Each year, there are Juneteenth celebrations on June 19th, across the United States.