Today is Juneteenth, the day that African-American slaves in Texas were informed that they were supposed to have already been emancipated two and a half years earlier.
On January 1, 1863, President Abraham Lincoln issued the Emancipation Proclamation. The proclamation declared (in summary) "that all persons held as slaves" within the rebellious states "are, and henceforward shall be free." Although this proclamation was issued, slavery did not end immediately. Due to being more geographically isolated, a lot of slaveholders migrated to Texas to escape the fighting of the Civil War.