Industry grew in the Northeast during the early to mid-1800s because the Northeast had

There were several reasons industry grew in the Northeast during the early to mid 1800s including:

1) Industrial Revolution in Europe - During the late 1700's, Europe was going through the Industrial Revolution. This revolution saw a change in the structure of businesses and how goods were produced. Individuals started to rely more on machines and unskilled labor than any other time in European history. The ideas of this revolution caught on in American cities in the Northeast.

2) Government support - During the 19th century, government supported industrialization and the development of American businesses in many different ways. This includes the implementation of tariffs and giving land grants/loans to railroad companies in order to start building the transcontinental railroad.