The Harmony Mills were the primary catalyst in transforming Cohoes into a prominent 19th century manufacturing center. Under the successful local management of Robert and David John Johnston and Thomas Garner and Company, a single cotton mill expanded into an industrial complex of six mills often called the Lowell of New York State. From the late 1860s through the 1880s, the mills were the largest cotton fabric manufacturing establishment in the United States. Mill #3, the largest in the complex, measured 1,185 feet long, 75 feet wide, and five stories high, and was considered among the greatest technological achievements in American cotton mill design. In 1860, more than half of the employees were Irish immigrants, and by 1869 the mills employed 3,100 people, two-thirds of them women. By 1880, after extensive recruitment in Quebec, more than one-third of the workers were French-Canadian. Children as young as nine also worked there to help support their families, as adult workers earned as little as 50 cents a day for an exhausting 72-hour, six-day work week, though many were drawn by the promise of steady employment and company housing.