Final answer:
Northern cities that experienced significant growth in the early 1800s include New York, NY; Boston, MA; and Philadelphia, PA, primarily due to industrialization and advancements in transportation such as the steam engine and infrastructure like the Erie Canal.
Step-by-step explanation:
The northern cities that grew greatly in the early 1800s include New York, NY; Boston, MA; and Philadelphia, PA. During this time, the attractions of city life and employment opportunities grew exponentially due to rapid changes in industrialization. With the development of the steam engine, factories no longer needed to be located near bodies of water, allowing them to be constructed closer to urban centers. This industrial expansion encouraged significant population growth in these cities.
New York City, in particular, saw a massive population increase. Factors such as its port on the Atlantic Ocean, the navigable Hudson River, and the opening of the Erie Canal in 1825 helped solidify its advantages in transportation and trade. Boston and Philadelphia also experienced considerable growth. Philadelphia, as an important port city with a diverse immigrant population, nearly tripled in size by the early 1900s.