|Image source: My Plain View dot com|
Juneteenth is the oldest nationally celebrated commemoration of 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 Galveston, 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. The Emancipation Proclamation had little impact on the Texans due to the minimal number of Union troops to enforce the new Executive Order. However, with the surrender of General Lee in April of 1865, and the arrival of General Granger’s regiment, the forces were finally strong enough to influence and overcome the resistance.
Later attempts to explain this two and a half year delay in the receipt of this important news have yielded several versions that have been handed down through the years. Often told is the story of a messenger who was murdered on his way to Texas with the news of freedom. Another, is that the news was deliberately withheld by the enslavers to maintain the labor force on the plantations. And still another, is that federal troops actually waited for the slave owners to reap the benefits of one last cotton harvest before going to Texas to enforce the Emancipation Proclamation. All of which, or neither of these version could be true. Certainly, for some, President Lincoln's authority over the rebellious states was in question For whatever the reasons, conditions in Texas remained status quo well beyond what was statutory.
General Order Number 3
One of General Granger’s first orders of business was to read to the people of Texas, General Order Number 3 which began most significantly with:
"The people of Texas are informed that in accordance with a Proclamation from the Executive of the United States, all slaves are free. This involves an absolute equality of rights and rights of property between former masters and slaves, and the connection heretofore existing between them becomes that between employer and free laborer."
The reactions to this profound news ranged from pure shock to immediate jubilation. While many lingered to learn of this new employer to employee relationship, many left before these offers were completely off the lips of their former 'masters' - attesting to the varying conditions on the plantations and the realization of freedom. Even with nowhere to go, many felt that leaving the plantation would be their first grasp of freedom. North was a logical destination and for many it represented true freedom, while the desire to reach family members in neighboring states drove the some into Louisiana, Arkansas and Oklahoma. Settling into these new areas as free men and women brought on new realities and the challenges of establishing a heretofore non-existent status for black people in America. Recounting the memories of that great day in June of 1865 and its festivities would serve as motivation as well as a release from the growing pressures encountered in their new territory. The celebration of June 19th was coined "Juneteenth" and grew with more participation from descendants. The Juneteenth celebration was a time for reassuring each other, for praying and for gathering remaining family members. Juneteenth continued to be highly revered in Texas decades later, with many former slaves and descendants making an annual pilgrimage back to Galveston on this date. 
In all the non-slave-holding States, in violation of that good faith and comity which should exist between entirely distinct nations, the people have formed themselves into a great sectional party, now strong enough in numbers to control the affairs of each of those States, based upon the unnatural feeling of hostility to these Southern States and their beneficent and patriarchal system of African slavery, proclaiming the debasing doctrine of the equality of all men, irrespective of race or color--a doctrine at war with nature, in opposition to the experience of mankind, and in violation of the plainest revelations of the Divine Law. They demand the abolition of negro slavery throughout the confederacy, the recognition of political equality between the white and the negro races, and avow their determination to press on their crusade against us, so long as a negro slave remains in these States.
For years past this abolition organization has been actively sowing the seeds of discord through the Union, and has rendered the federal congress the arena for spreading firebrands and hatred between the slave-holding and non-slave-holding States. 
1. History of Juneteenth, Juneteenth dot com
2. DECLARATION OF CAUSES: February 2, 1861
A declaration of the causes which impel the State of Texas to secede from the Federal Union.
Texas State Library and Archive Commission
Note: A search for "slave" finds 21 references to "slave", "slave-holding" and "slavery." A search for African yields "African", "African race" and "African slavery", for which are the following associated, clear expressions that had nothing at all to do with the nebulous "states rights" dodge:
We hold as undeniable truths that the governments of the various States, and of the confederacy itself, were established exclusively by the white race, for themselves and their posterity; that the African race had no agency in their establishment; that they were rightfully held and regarded as an inferior and dependent race, and in that condition only could their existence in this country be rendered beneficial or tolerable.