During the Civil War, the North had a larger population, greater access to the navy, more industrial power and better access to gunpowder. However, the South benefited from familiarity with their own terrain, being resourceful and having the ability to produce all the food they needed.
During the Civil War, the North had a population of 21 million, whereas the South was just 9 million. Despite this, the South managed to produce an army that was just as big as the North's. Alongside this, the North had better access to industrial power. It made 97 percent of firearms and had more railroads per square mile. In contrast, the South did not have its own rifle works. Another of the North's military advantages was that it had control over the navy, which meant it could block a lot of the South's gunpowder imports.
While the North had considerable military advantages, the South was familiar with its own terrain, which made it easier for them to deter northern invaders. In addition, they managed to produce multiple armories by the end of the war. The South's resourcefulness extended to being able to produce much of their own food, which meant they did not have to rely on the North's industrialization.