There are various reasons for the increase in the formation of cities in the United States during the late 1800s and early 1900s. Here are some possible reasons:1. Industrialization: The rise of industrialization during this time led to the growth of cities as people moved from rural areas to urban centers in search of employment opportunities. Factories and industries were largely concentrated in cities, attracting workers to settle there.2. Technological advancements: Advancements in transportation technologies, such as railroads, made it easier for people to travel to cities and for goods to be transported to and from urban areas. This facilitated the growth and connectivity of cities, making them more attractive to people.3. Immigration: The late 1800s and early 1900s saw a significant influx of immigrants to the United States. Many of these immigrants settled in cities where they could find jobs and establish communities with others from their home countries.4. Economic opportunities: Cities offered a wide range of economic opportunities, including jobs, better wages, and access to markets. As cities grew, they became centers of trade, commerce, and industry, attracting people seeking economic advancement and better livelihoods.5. Urbanization and urban planning: The development of city infrastructure, including the construction of buildings, roads, and utilities, contributed to the growth of cities. Urban planning efforts aimed at improving living conditions and creating public amenities also made cities more attractive places to live.6. Social and cultural factors: The growth of cities allowed for the development of diverse social and cultural scenes, attracting people who sought intellectual, artistic, and entertainment opportunities that were more prevalent in urban areas.Overall, a combination of industrialization, technological advancements, immigration, economic opportunities, urbanization efforts, and social and cultural factors contributed to the increase in the formation of cities in the United States during this period.