How many people lived in industrial cities?

The population of industrial cities varied greatly depending on the time period and location. During the peak of the Industrial Revolution in the 19th century, cities like Manchester and Birmingham in the UK saw populations grow into the hundreds of thousands, with Manchester reaching around 300,000 by 1851. In the United States, cities like Chicago and New York also experienced rapid population increases, often exceeding a million residents. Today, many industrial cities continue to house millions, reflecting ongoing urbanization and industrial activity.