Why were so many manufacturing plants built near large cities?

The list is huge as to the reasons. That's where the workers are The power supply required The infrastructure and logistic support to manufacture and ship product. Really where else would you build In buck f nowhere. Hire the six farmers that live within fifty miles Build your own power plant to produce the power that large industry requires. I think very soon a small city would spring up to support the industry's needs. What do you think city's started from. Banks and restaurants