How did slavery in the South affect the economy in the North?

Actually its the other way around.

The North already had a tariff in place that benefited their industries but it was devastating to Southern industries. The Civil War was almost sparked ~30 years prior over this very tariff ("The Tariff of Abominations" and the "Nullification Crisis" under President #6 Andrew Jackson).

The North used to practice slavery too but it died out only because Northern agriculture was seasonal so slavery was not a profitable business model for them (in other words it wasn't some moral epiphany that slavery was wrong that made them stop). The South had year-round agriculture so slavery was more profitable there.

The major Northern and Southern industries held different niches and thus were not in competition with one another so slavery in the South didn't create economic issues in the North... it only created POLITICAL issues.

Slavery helped the mono=cultural south:

- With the invention of the cotton gin, more people wanted to have slaves to build their business on cotton.

- More slaves = more labor = more money

- South's economy was based on slaves, but the North couldn't relate (they did not have the right environment to grow crops, so their industry was based on their cities and development/manufacturing).

- Slavery in the south = more cotton in south = manufacturing cotton in North = trade in North.

I wouldn't exactly say slavery in the South helped the North. But then the South did not want higher tariffs because of their cotton industry, and the North wanted higher tariffs. (Causing disputes which eventually lead to the civil war along with other disagreements).

I hope this helps :]

Extra workers, Free labor = lots more income

haha u.s. history. i hate that class.