The abolition of slavery in the United States occurred in stages, with the key milestones being the Emancipation Proclamation in 1863 and the Thirteenth Amendment in 1865. Direct answer

• Emancipation Proclamation: Issued by President Abraham Lincoln on January 1, 1863, it declared that enslaved people in Confederate-held territory were to be freed. It did not immediately free all enslaved people nationwide, but it reframed the war aims and authorized the recruitment of Black soldiers into the Union Army. [emancipation context historically, 1863]
• Thirteenth Amendment: Ratified on December 6, 1865, this amendment formally abolished slavery throughout the United States and banned involuntary servitude, except as punishment for a crime whereof the party shall be duly convicted. This marked the constitutional end of slavery in the country. [constitutional end, 1865]

Important nuances

• Freedom was uneven in the immediate aftermath of the Proclamation; enforcement depended on Union military advances and control of territory. Some enslaved people in border or Union-controlled areas gained freedom earlier through manumission and self-emancipation, while others remained enslaved until 1865. [contextual nuance, 1863–1865]
• Texas and a few other regions did not fully realize emancipation until the Union victory and subsequent enforcement, culminating in Juneteenth on June 19, 1865, when the news and orders reached Galveston, Texas. About 250,000 enslaved people in Texas were declared free then. [regional detail, 1865]

If you’d like, I can provide a concise timeline of the major events and how emancipation spread across the country, or summarize common misconceptions about when slavery ended in specific states.