Industrialization
100

Industrialization came about in the North due to the reliance on factories as well as this labor source:

New immigrants. Most emigration to the United States took place in Northern cities. 

200

Due to industrialization, there were far more of these in the north and west than in the south of the United States:

1. Railroads

2. Factories

3. New Immigrants

300

Some workers organized into these, intended to force employers to reduce working hours, increase pay, and improve safety conditions.

Labor unions.