Juneteenth is the oldest known celebration commemorating the ending of slavery in the United States. Dating back to 1865, it was on June 19th that the Union soldiers, led by Major General Gordon Granger, landed at Galvestion, Texas with news that the war had ended and that the enslaved were now free. Note that this was two and a half years after President Lincoln's Emancipation Proclamation - which had become official January 1, 1863.