The Industrial Revolution led to a massive shift in how and where many people lived. Prior to the spread of industry in Europe and North America, most people lived and worked on farms. Many consumer goods were made in people's homes. At the start of the Industrial Revolution, many factories produced part of a product and had sent it out to people's homes to be completed there. It did not take long for factory owners to realize that it would be more efficient to have all their workers centralized at the factories. Cities soon grew around these factories as more people shifted from agrarian work in the countryside to industrial work in cities.

One further way that the Industrial Revolution impacted the growth of cities was the development of better transportation. Before, it was slow, difficult, and expensive to bring many goods to market. That meant that markets were local and small. People had to live relatively close to where things were produced. During the Industrial Revolution, railroads were expanded, roads were built, canals were dug, and steamships were improved. This allowed cities located far away from the sources of raw materials to flourish, and more diversified and robust markets became established there.

During the Industrial Revolution, the center of the economy shifted away from agriculture and towards manufacturing. Manufacturing, as it became increasingly large and important, located itself in large factories, employing hundreds of employees in a single location.

Factories, though not wonderful places of employment, often offered better wages than agricultural work, so laborers flocked to them. As workers gathered in towns and cities to find factory work, these areas grew to service worker needs for housing near the factories, for food they could no longer grow themselves, and for other necessities. Early factories, such as textile factories, often clustered in a single location near raw materials, such as wool, or the water the needed to help power their industries. These factory clusters, such as in the north of England (sheep country) in places like Manchester, led to rapid urban growth.

England was the first country to industrialize in a large-scale way, primarily around the textile industry. As the first to experience a massive shift from an agrarian lifestyle centered around small villages to populations aggregating in cities, England simply wasn't prepared for the change. Conditions were often appalling around the factories, but over time, despite the sometimes terrible conditions, industrialism improved the standard of living. Cheaper cloth meant people could buy far more clothing, helping to prevent the spread of disease and giving people more protection against the cold. Even the poor often ate better than they had on the farms, leading to increases in family size. At the higher echelons, people gained great wealth or prospered as a rising middle class. This also expanded cities and towns as increasing wealth led people to build bigger houses, buy more goods, and want access to more leisure activities. In a post-industrial world, people continued to like and desire the amenities and conveniences associated with urban life.

The primary answer is the employment boom that accompanied the Industrial Revolution. The factories were located in the towns and attracted the rural population with new jobs. In fact, the Industrial Revolution brought more people into the cities than ever before. For instance, in 1850 Great Britain had more people living in the cities than the countryside. This occurred later for the United States as well.

Along with the employment came wealth. As people became employed in these cities and found a little more wealth than they were used to, they settled down with homes. These homes produced children and the families began to grow. Schools were created and more businesses popped up along the way. All of this only fueled the population boom in cities around the time of the Industrial Revolution.