The Pearl incident was the largest recorded nonviolent escape attempt by enslaved people in United States history. On April 15, 1848, seventy-seven slaves attempted to escape Washington, D.C. by sailing away on a schooner called The Pearl. Their plan was to sail south on the Potomac River, then north up the Chesapeake Bay and Delaware River to the free state of New Jersey, a distance of nearly 225 miles (362 km). The attempt was organized by both abolitionist whites and free blacks, who expanded the plan to include many more enslaved people. Paul Jennings, a former slave who had served President James Madison, helped plan the escape.

The escapees, including men, women, and children, found their passage delayed by winds running against the ship. Two days later, they were captured on the Chesapeake Bay near Point Lookout, Maryland, by an armed posse traveling by steamboat. As punishment, the owners sold most of the escapees to traders, who took them to the Deep South. Freedom for the two Edmonson sisters was purchased that year with funds raised by Henry Ward Beecher's Plymouth Congregational Church in Brooklyn, New York.

When the ship and its captives were brought back to Washington, a pro-slavery riot broke out in the city. The mob attempted to attack an abolitionist newspaper and other known anti-slavery activists. Extra police patrolled for three days to try to contain the violence until the unrest ended. The episode provoked a slavery debate in Congress, and may have influenced a provision in the Compromise of 1850 that ended the slave trade in the District of Columbia, although not slavery itself. The escape inspired Harriet Beecher Stowe in writing her novel Uncle Tom's Cabin (1852), in which people in slavery dreaded being "sold South", and increased support for abolitionism in the North.

Three white men were initially charged on numerous counts with aiding the escape and transporting the captives; the captains Daniel Drayton and Edward Sayres were tried and convicted in 1848. After serving four years in prison, they were pardoned by President Millard Fillmore in 1852.

Like the surrounding states of Maryland and Virginia and others in the South, Washington, D.C., was a "slave society" as defined by the historian Ira Berlin in his Many Thousands Gone: A History of Two Centuries of American Slavery. It supported a major slave market and was a center of the domestic slave trade; with its connection to the Chesapeake Bay by the Potomac River, Washington was an important transit point for captives being shipped or marched overland from the Upper South to markets or owners in the Deep South. Numerous families in the city actively enslaved people, generally forcing them to act as domestic servants and artisans. Some hired out their slaves to work as servants on the waterfront and in other urban jobs.

In 1848, free blacks outnumbered slaves in the District of Columbia by three to one. Abolitionists, both free blacks and whites, were active in the city in trying to end the slave trade and slavery. In addition, since the 1840s, there had been an organized group that supported the Underground Railroad in the district. The abolitionist community demonstrated in its planning for the escape that it could act in a unified way. They sought to plan an event that would capture the attention of Congress and the country to promote an end to slavery in the District of Columbia. White supporters included the abolitionists William L. Chaplin and Gerrit Smith of New York, who helped find the captain Daniel Drayton and pay for a ship. The black community made the project its own, notifying so many families that soon there were 77 slaves who wanted to be part of the escape.

For two days prior to the slaves' escape, many city residents had been celebrating the news from France of the expulsion of King Louis Philippe and the founding of the French Second Republic, with its assertion of universal human rights and liberty. Some free blacks and slaves were inspired by plans to gain similar freedoms for American slaves. People gathered to hear addresses in Lafayette Square in front of the White House. As the historian John H. Paynter recounted:

Among the addresses which aroused the large crowd to enthusiasm were those of Senator Patterson of Tennessee and Senator Foote of Mississippi. The former likened the Tree of Liberty to the great cotton-wood tree of his section, whose seed is blown far and wide, while the latter spoke eloquently of the universal emancipation of man and the approaching recognition in all countries of the great principles of equality and brotherhood."