Eli Whitney is granted a patent for the cotton gin.

A cotton ginmeaning "cotton engine"is a machine that quickly and easily separates cotton fibers from their seeds, enabling much greater productivity than manual cotton separation. The fibers are then processed into various cotton goods such as calico, while any undamaged cotton is used largely for textiles like clothing. The separated seeds may be used to grow more cotton or to produce cottonseed oil.

Handheld roller gins had been used in the Indian subcontinent since at earliest AD 500 and then in other regions. The Indian worm-gear roller gin, invented sometime around the 16th century, has, according to Lakwete, remained virtually unchanged up to the present time. A modern mechanical cotton gin was created by American inventor Eli Whitney in 1793 and patented in 1794.

Whitney's gin used a combination of a wire screen and small wire hooks to pull the cotton through, while brushes continuously removed the loose cotton lint to prevent jams. It revolutionized the cotton industry in the United States, but also led to the growth of slavery in the American South. Whitney's gin made cotton farming more profitable, so plantation owners expanded their plantations and used more slaves to pick the cotton. Whitney never invented a machine to harvest cotton, it still had to be picked by hand. The invention has thus been identified as an inadvertent contributing factor to the outbreak of the American Civil War. Modern automated cotton gins use multiple powered cleaning cylinders and saws, and offer far higher productivity than their hand-powered precursors.

Eli Whitney Jr. (December 8, 1765 – January 8, 1825) was an American inventor, widely known for inventing the cotton gin, one of the key inventions of the Industrial Revolution that shaped the economy of the Antebellum South.Although Whitney himself believed that his invention would reduce the need for enslaved labor and help hasten the end of southern slavery, Whitney's invention made upland short cotton into a profitable crop, which strengthened the economic foundation of slavery in the United States and prolonged the institution. Despite the social and economic impact of his invention, Whitney lost many profits in legal battles over patent infringement for the cotton gin. Thereafter, he turned his attention into securing contracts with the government in the manufacture of muskets for the newly formed United States Army. He continued making arms and inventing until his death in 1825.