The significant historical event in the 19th century that centered on the abolition of slavery in the United States was the American Civil War (1861-1865). The conflict arose primarily from tensions between the northern states, which opposed slavery, and the southern states, which embraced it as a cornerstone of their economy. The war culminated in the Emancipation Proclamation of 1863, which declared the freedom of all enslaved people in the rebellious states. The Civil War ultimately led to the passage of the 13th Amendment, formally abolishing slavery, and marked a profound turning point in American history, reshaping the nation’s social and political dynamics.