GOVT 2305 doesn't cover local government, or the various ways that cities can be designed. Cities are one of the many components of local government - along with counties, independent school districts, and such - so it fits within the greater concept of federalism. The creation of local governments is one of the powers delegated to the states. Cities also enforce states laws, which can include the enforcement of national laws.
With that out of the way, here is a look at how one of the older cities in the US was created.
Enjoy.