The History of Juneteenth: From Freedom Delayed to National Holiday

Juneteenth (June 19, 1865): This date marks the effective end of slavery in practice. It represents the moment when federal authority, backed by military force, reached the last Confederate holdout in Texas and enforced the Emancipation Proclamation, liberating the final large group of enslaved people.

https://govfacts.org/history/the-history-of-juneteenth-from-freedom-delayed-to-national-holiday/