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The President's House in Philadelphia

Systems & Methods of Slavery



The trans-Atlantic slave trade began in the early 1500s with the arrival of Dutch and Portuguese explorers and did not officially end end until it was outlawed by Brazil in 1888. “Chattel slavery” — the legal ownership of individuals men, women and children by others who could sell them at will existed in all the Americas from Canada to Chile.

During these years, more than 10 million Africans were kidnapped from West and Central Africa and brought to the Americas. Of those, about five percent came to the pre-Revolutionary United States.

Britain outlawed the slave trade in 1807, and Congress made the trans-Atlantic slave trade to the United States illegal in 1808, the earliest date permitted by the constitution for such a ban; but the buying, selling and ownership of race-based enslavement continued. The increase of the population of enslaved Africans after 1808 was the result of births to enslaved mothers already here.


This plan shows the President’s House as it was in 1781 when Robert Morris contracted to purchase it. Though modified by President Washington before he moved in, this plan is consistent with later descriptions of the house during Washington’s presidency.



Slavery came to the Delaware River Valley in the 1630s, when this was part of New Netherlands. British settlers, including many Q uakers, expanded slavery once they began moving to the new colony of Pennsylvania after 1680. By 1790, Africans and their descendants were concentrated in the Chesapeake region of Maryland, Virginia, and southern Delaware and in the Low country of the Carolinas and Georgia where plantations dominated.


In 1790 tobacco and sugar processing, shipbuilding, and trade with the West Indies were thriving. Much of this still involved enslaved labor, which continued to dominate many political and economic considerations.


A newly developed global economy created demand for raw goods such as rice, tobacco and cotton grown in the South. Sugar and coffee from plantations in the West Indies, were traded for rum and textiles, produced in the North.


From the President’s House, Washington and Adams led a nation of almost four million according to the first census in 1790; it grew to more than five million by 1800.

Total US.Population3,929,2145,308,483
Free Africans59,150108,500
Enslaved Africans694,280893,602

The population of enslaved Africans was also increasing from just under 700,000 in 1790 to nearly 900,000 in 1800. As Washington and Adams governed the new nation, slavery continued to grow as well. By 1800 one out of every six people in America was enslaved.

In the Ohio Territory, the Northwest Ordinance of 1787 prohibited slavery, even though decades more were needed to end it there completely. In the 1790s, Congress admitted Kentucky and Tennessee as slave states and Vermont as a free state.


1662Virginia law decrees that children of African American mothers “shall be bond or free according to the condition of the mother.”
1705Virginia lawmakers fix the status of blacks as slaves when they decree ‘All servants imported and brought into the Country...who were not Christians in their native Country... shall be accounted and be slaves.” They also fix slaves as real estate which can be passed on from generation to generation. In addition slaves who resist their master can be disciplined or killed without penalty.
1780Pennsylvania becomes the first government in the Western Hemisphere to begin an abolition of slavery with the Gradual Abolition Act. The law allows citizens of other states tern- porarily residing in Pennsylvania to hold domestic slaves for up to 6 months, after which those enslaved Africans have the right to manumission. Members of the U.S. Congress (then the only branch of the federal government) and their personal slaves are specifically exempted from the state law.
1780The Pennsylvania Gradual Abolition Act prohibits any further importation of enslaved Africans into the state and guarantees that the future children of enslaved Pennsylvania mothers will be born free.
1787Slavery is made illegal in the Northwest Territory.
1787The U.S Constitution states that Congress may not ban the slave trade until 1808.
1788Pennsylvania state legislature amends the 1780 law, closing loopholes. The 1788 amendment prohibits a Pennsylvania master from transporting a pregnant enslaved woman out of state (so the child will be born enslaved), from separating enslaved husbands and wives or children and parents, and requires a master to register the child of an enslaved mother within 6 months of birth. Non-resident slave-holders are prohibited from rotating their domestic slaves out of Pennsylvania to prevent those enslaved Africans from qualifying for manumission under the state law.
1791The first year that the Washington’s violate the 1788 amendment by bringing back into Pennsylvania enslaved Africans who had been transported out of state to prevent their obtaining their freedom. This illegal out-of-state rotation of the President’s House enslaved Africans continues until the end of Washington’s presidency
1791An amendment is proposed (and fails) in the Pennsylvania Assembly to exempt all slave-holding officers of the federal government (including Washington, his Cabinet, and the Supreme Court) from the Gradual Abolition Act. This was an attempt to make the state more hospitable to slave-holders in hopes of having Philadelphia become the permanent capital of the United States. The proposal is withdrawn before debate after heated opposition from the Pennsylvania Abolition Society.
1793The U.S. Congress passes and Washington signs the Fugitive Slave Act. The U.S. Constitution (Article IV, Section 2) guaranteed the right of a slave-holder to recover a runaway slave.
1808The first year that children of enslaved Pennsylvania mothers are freed of their indentures under the 1780 Gradual Abolition Act. The first children born after March 1, 1780 turn 28 in this year. Legally, they had been indentured servants (not slaves) and are now free.
1808United States Bans Slave Trade Importing African slaves is outlawed, but smuggling continues.
1820The Missouri Compromise bans slavery north of the southern boundary of Missouri.
1847The Pennsylvania state legislature frees all enslaved Africans remaining in Pennsylvania.
1860Compromise of 1850 includes a stronger Fugitive Slave Act intended to make it easier for slaveholders to retrieve fugitives from slavery.
1857The Dred Scott case holds that Congress does not have the right to ban slavery in states and, that slaves are not citizens.

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