The first slaves came to the Americas in 1619 and continued to be brought from West Africa to the Americas until American banned the Transatlantic slave trade in 1807. However, slavery was still legal under federal law until the Thirteenth Amendment was passed on January 31, 1865 (246 years).

Just like the U.S. Constitution, the first state constitutions stated that all men were created equal, yet they did not mention the fact that some men (and women) were held as slaves. They did not even include the word "slavery" in their state constitutions. Over time, states changed their constitutions to limit specific practices, such as the slave trade. For instance, in 1744, Connecticut and Rhode Island outlawed the slave trade (after 125 years). When states did vote to do away with slavery, they did not immediately free the slaves. Many passed gradual emancipation laws and most even paid slave owners for the loss of their slaves. Slaves, however, received no reparation for their time as a slave.

• 1777: The Constitution of Vermont banned slavery (while still independent).

  • "That all men are born equally free and independent, and have certain natural, inherent and unalienable rights; amongst which are, the enjoying and defending life and liberty-acquiring, possessing and protecting property and pursuing and obtaining happiness and safety. Therefore, no male person, born in this country, or brought from overseas, ought to be holden by law to serve any person, as a servant, slave, or apprentice, after he arrives to the age of twenty-one Years; nor female, in like manner, after she arrives to the age of eighteen years; unless they are bound by their own consent after they arrive to such age; or bound by law for the payment of debts, damages, fines, costs, or the like." - Constitution of Vermont Chapter 1 Section I- July 4, 1786

• 1780: Pennsylvania passed gradual emancipation laws.

• 1783: Massachusetts Supreme Court ruled slavery illegal based on the 1780 Constitution of Massachusetts. Slavery ended in Massachusetts by the time of the census in 1790.

• 1783: New Hampshire Constitution contains a bill of rights that is interpreted as ending slavery. In 1857, a law was approved that formally prohibited slavery.

• 1784: Connecticut and Rhode Island added gradual emancipation laws.

• 1799: New York State began gradual abolition of slavery. A law was approved in 1817 that freed all remaining slaves on July 4, 1827.

• 1804: New Jersey began the gradual abolition of slavery.

• The remaining states joined the union as a free or a slave state due to Federal Agreements like the North West Ordinance, Compromise of 1850, and others. The new states did not mention slavery in their state constitutions (except Texas which explicitly makes slavery legal in its state Constitution).

• When the Civil War breaks out Lincoln issues the Emancipation Proclamations which frees the slaves in the 11 Confederate States.

• The Thirteenth Amendment frees all the slaves in the U.S.