How and why did slavery expand in the antebellum USA?

Two factors led to the expansion of slavery in the United States: Eli Whitney's invention of the cotton gin and Britain's industrial revolution.

When the United States Constitution was adopted in 1787 slavery was slowly dying out. And the Founding Fathers, north and south, expected that to continue.

In the late 18th century the spinning jenny and the power loom were invented in Britain. These inventions were an important part of the industrial revolution. They greatly increased the demand for raw cotton as cotton was especially well suited to the technology.

Long staple Sea Island Cotton was grown as a commercial crop in Georgia. However, there was a constant battle with an invasive weed: Short Staple Cotton which grew everywhere. It was useless as it was so full of seeds it had no value. Then in 1790 Eli Whitney invented the cotton gin. Using a cotton gin one man could clean as much cotton from its seeds as 50 men could do in a day by hand. Very quickly many people saw the profits to be made using slaves to raise short staple cotton on plantations and selling it to British textile mill owners. And the raw cotton was so cheap that the British, after making the cloth, could sell it at a profit to the poorest people in their Empire. Calico means Calcutta cloth. Britain was a trading nation; money poured in to ship owners who transported raw cotton and cotton cloth. And Britain was becoming a manufacturing nation and money ported in to spinning and weaving mill owners. And the textile industry produced a demand for stationary stream engines which could operated mills when rivers froze in winter and during periods of low water in summer so the textile industry was important in creating iron and later steel manufacturing industries. And most of the cotton was grown by slaves in the United States. By 1860 80 per cent of all British raw cotton was imported from America.

Cotton plantations expanded up and down navigable rivers in the south, the Mississippi and the Tennessee Rivers especially. As as the property along the rivers filled up railroads were built to haul cotton form inland areas to the closest port. In 1860 the south had 9,000 miles of railroad out of a total of 30,000 miles in the whole country. The first north south trunk line was the Mobile and Ohio and the Illinois Central which ran from Mobile, AL to Chicago, IL and the first east west trunk line was the Atlanta and Western with other connecting lines which ran from Savannah, GA to Memphis, TN. Both lines ran through cotton country and carried cotton to the closest ports.

In 1790 there were almost 700,000 slaves in the us. By 1860 there were over 3,954,000 slaves, over 5 times as many, That increase was due to raising cotton. However, not all slaves worked on cotton plantations. For example, steam boat companies and railroads also owned slaves.

The "antebellum" period was right before the start of the civil war.

Around this time, new inventions like factories, cotton gin, and trains were speeding up production.

This meant that more slaves would have to be picking cotton in the fields to keep up.

Also, there were new states being added to the union.

Southern farmers wanted them to be pro-slavery states, while northern politicians wanted them to be slave-free.

So slavery began expanding west.

Then we had a war (it wasn't over slavery btw)

After the war, slavery "stopped"

There are plenty of books by professional historians that explain this. Why aren't you just reading one of those, instead of getting wrong answers from random idiots on the internet? Is it because you're just stupid?

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