Not really. It marked the day Texas freed the slaves. It was never recognized as a national holiday until now
No...Texas didn't free the slaves...the Union Army did. The Republican Union Army that is.
I pointed out on another thread that we should celebrate President Lincoln's Emancipation Proclamation on September 22 (the day he wrote it - it became effective on January 1 but that is New Years Day - a nationalist holiday already)
June 19, 1865, is when the slaves in Galveston learned that they were free because the war was over. Black people elsewhere in Texas who were being held as slaves would not have heard the news until later, and slavery was still legal in Kentucky and other slave states which had not seceded until Dec. 6, 1865 (although in practice it may have been hard to force anyone to work as a slave during the months before ratification was completed).
Not only that, it was not the day the last slaves were freed. There were two border states where emancipation didn’t arrive until the 13th Amendment passed in December of 1865.