Juneteenth, the nation's most recent federal holiday, is celebrated by Americans on June 19 to commemorate the end of slavery in the United States and has a history going back to the 1860s.

Juneteenth, which commemorates the legacy of emancipation, means that many government offices are to close amid celebrations.

Juneteenth is the oldest nationally celebrated commemoration of the ending of slavery in the United States. Here's some of its history, and how it came to be a national holiday. President Abraham Lincoln signed the Emancipation Proclamation into law on Jan. 1, 1863, freeing all slaves in the Confederate states — on paper, at least.