The Emancipation Proclamation issued by Abraham Lincoln in 1862, which would go into effect on January 1, 1863. This only applied to states under Confederate control and did not include Tennessee.
Juneteenth or Freedom Day, is a holiday that commemorates the announcement of the abolition of slavery in Texas in June 1865, and more generally the emancipation of African-American slaves throughout the Confederate.
The Eighth of August is the day celebrated in East Tennessee and Kentucky and probably some other places as well. It was the only day blacks in Knoxville were allowed to visit Chilhowee Park. Read a little about Andrew Johnson's slaves- Sam and Dolly were probably the best known. Sam Johnson started a Freedman's school in Greeneville: Link
Finally, on October 24, 1864, Andrew Johnson freed all the slaves in the state of Tennessee. Read more about Andrew Johnson's role here: Link
It is fitting the the celebration will held on Saturday August 8th at Chilhowee Park. You can read the details here. Link
The day will start with a service at Freedmen's Cemetery, adjacent to Knoxville College- a place where several of Andrew Johnson's former slaves are buried.