A cotton mill is a building that houses spinning or weaving machinery for the production of yarn or cloth from cotton, an important product during the Industrial Revolution in the development of the factory system.
Although some were driven by animal power, most early mills were built in rural areas at fast-flowing rivers and streams, and used water wheels for power. The development of viable steam engines by Boulton and Watt from 1781 led to the growth of larger, steam-powered mills. They were built in a concentrated way in urban mill towns, such as Manchester. Together with neighbouring Salford, it had more than 50 mills by 1802.