I know you came here seeking answers to questions, but now I have questions for you: do cities in Indiana Annex their suburbs in the same way that a lot of cities west of the Mississippi do? The greatest example that I can give is Phoenix arizona. Phoenix is the fastest growing city in america, or at least one of them, but not because people keep moving there, it's because they keep annexing surrounding suburbs. That is something that does not happen in the northeast. So when you look at population density of American cities you will notice that the Northeast has some crazy density and the Southwest has almost none.

And to make an attempt at answering your question, some of those small townships are actually considered villages.