Most enslaved in the USA worked on plantations in the Southern states. These states had conditions and crops that were best suited to plantations and slave labour. ​
After the American Revolution states in the North gradually rejected slavery and by 1804 became Free States.​
As a result tensions grew between the North and South over the issue of slavery, runaway slaves often sought refuge in the North. ​
The campaign to end slavery in the whole of the USA was rooted in the North.​
