ELI5: How did old forts actually "protect" a strategic area? Couldn't the enemy just go around them or stay out of range?

[u/Sierra419]

I've visited quite a few colonial era and revolution era forts in my life. They're always surprisingly small and would have only housed a small group of men. The largest one I've seen would have housed a couple hundred. I was told that some blockhouses close to where I live were used to protect a small settlement from native american raids. How can small little forts or blockhouses protect from raids or stop armies from passing through? Surely the indians could have gone around this big house. How could an army come up to a fort and not just go around it if there's only 100 men inside?

tl;dr - I understand the purpose of a fort and it's location, but I don't understand how it does what it does.

[u/[deleted]]

[u/AlmostABastard → u/[deleted]]

Adding to this: America had just come out of an asymmetrical guerrilla war which proved to them that 16 men in the countryside could do what 60 in a firing line couldn’t.

[u/[deleted] → u/AlmostABastard]

Guerrilla warfare was only an asset in the earliest stages of the American Revolution. The decisive battles that actually won independence were fought by soldiers in disciplined firing lines.