On 16 October 1859 John Brown led eighteen men-thirteen whites and five blacks-into Harpers Ferry, Virginia.  Three other members of his force formed a rearguard at a nearby Maryland farm.  A veteran of the violent struggles between pro- and antislavery forces in Kansas, Brown intended to provoke a general uprising of African Americans that would lead to a war against slavery. The raiders seized the federal buildings and cut the telegraph wires. Expecting local slaves to join them, Brown and his men waited in the armory while the townspeople surrounded the building.  The raiders and the civilians exchanged gunfire, and eight of Brown's men were killed or captured.  By daybreak on 18 October, U.S. Marines under the command of Brevet Colonel Robert E. Lee stormed Brown's position in the arsenal's enginehouse and captured or killed most of his force. Five of the conspirators, including Brown's son Owen, escaped to safety in Canada and the North. Severely wounded and taken to the jail in Charles Town, Virginia, John Brown stood trial for treason against the commonwealth of Virginia, for murder, and for conspiring with slaves to rebel. On 2 November a jury convicted him and sentenced him to death.  Brown readily accepted the sentence and declared that he had acted in accordance with God's commandments.  Responding to persistent rumors and written threats, Henry A. Wise, governor of Virginia, called out state militia companies to guard against a possible rescue of Brown and his followers. On 2 December 1859, Brown was hanged in Charles Town.

The Harpers Ferry raid confirmed for many Southerners the existence of a widespread Northern plot against slavery.  In fact, Brown had raised funds for his raid from Northern abolitionists.  To arm the slaves, he ordered one thousand pikes from a Connecticut manufactory. Letters to Governor Wise betrayed the mixed feelings people held for Brown.  For some, he was simply insane and should not be hanged.  For others, he was a martyr to the cause of abolition, and his quick trial and execution reflected the fear and arrogance of Virginia's slave owners. Many Northerners condemned Brown's actions but thought him right in his conviction that slavery had to end. Brown's raid on Harpers Ferry and his execution further polarized North and South and made a resolution of the slavery issue the center of national debate.