In the 1860s, most factories were located in the North of the United States, mostly because the South was largely agricultural and remained this way for many years.
The main result of Columbus' voyages across the Atlantic was that a "New World" was discovered in which resources were plentiful--meaning that these resources were shipped back to England and Europe. Another result is that millions of Native people were killed or displaced.
The Great Migration, or the relocation of more than 6 million African Americans from the rural South to the cities of the North, Midwest and West from 1916 to 1970, had a huge impact on urban life in the United States.