The greatest impact on the spread of slavery was the invention of the cotton gin by Eli Whitney in 1793. This invention greatly increased the profitability of cotton by making it easier to separate cotton fibers from seeds, which in turn massively increased the demand for slave labor in the Southern United States, where cotton was a major crop.
Why the Cotton Gin Had the Greatest Impact
- The cotton gin dramatically boosted cotton production efficiency.
- It made cotton cultivation highly profitable, increasing demand for labor.
- This demand was met largely by enslaved Africans, expanding the institution of slavery in the South.
Other Factors in the Spread of Slavery
- The Atlantic slave trade driven by European powers fueled initial large-scale enslavement for plantation labor, especially for crops like sugar.
- The economic importance of colonies like those in the West Indies and legal, racial, and military factors supported the use of enslaved labor.
- Internal slave trade within the U.S. also expanded as demand and territorial expansion grew.
However, among these, the cotton gin was the singular technological development that transformed the scale and economic incentives for slavery in the 19th century United States in particular, making it the most impactful factor in its spread.
