Juneteenth: June 19th
"Now, therefore I, Abraham Lincoln, President of the United States,...order and declare that all persons held as slaves within said designated States, and parts of States, are, and henceforward shall be free..."
Juneteenth is the celebration of the anniversary of the Emancipation Proclamation which was issued by US President Abraham Lincoln on January 1st, 1863. The proclamation gave the Southern slaves their freedom and is considered an important benchmark in the African-American struggle for freedom and equality.
The word "Juneteenth" comes from the words "June" and "19th", which according to southern folklore is when the slaves of Texas first learned of their freedom. Though technically freed in 1863, the slaves did not learn of their freedom until the arrival of the Union soldiers on June 19th, 1865. This was after the end of the Civil War and 2 1/2 years after the proclamation was first issued.
The Emancipation Proclamation is considered the catalyst that ended slavery. But at the time the proclamation was issued it really did not free anyone since the Confederate states did not recognize President Lincoln's authority. It was not until after the Civil War had ended that the 13th Amendment to the US Constitution, ratified in 1865, officially outlawed slavery.
Juneteenth began as a celebration by ex-slaves and has continued to be observed by African-Americans in the US South. Recently there have been efforts to bring a wider audience to the celebrations.