Illinois has thousands of local government bodies. Here is one reason for the large number:

Illinois was not unique in its decentralized, generous incorporation and annexation terms or in witnessing the end of the city’s physical expansion in the early twentieth century, phenomena that collectively encouraged fragmented jurisdictions in many metropolitan areas. Relatively unique, however, was Illinois’s strict constitutional limit on local debt, which prompted many suburbanites to create new governments rather than expand the charge of existing ones when new needs arose. Until amended in 1970, the Illinois Constitution restricted local borrowing to less than 5 percent of assessed valuation. This restriction made it difficult to finance big projects, especially for governments in small or rapidly growing places where property assessment increases often lagged years behind the need for services and infrastructure. Residents created new school districts to build high schools, for example, rather than extend elementary school districts’ responsibility into the upper grades (as in most other states). They also created a wide array of special-purpose governments to perform specific functions (like fire protection, building and managing parks, and managing sanitation) rather than expanding municipal functions. By 1970 there were 1,239 local governments in the six-county Chicago region: 280 incorporated municipalities, 121 township districts (with responsibility over unincorporated territory), 384 school districts and 449 special-purpose districts.”

On the one hand, you would not want small government bodies amassing large debts. How would they pay it off? How might servicing the debt affect their ability to provide local services?

On the other hand, this paragraph describes the downside of the debt limits. Have new needs or need more resources? Form a new government body in order to take on debt and pursue your goal.

Once these government bodies are established and raise money, they take on a life of their own. They live out their mandate. They provide local services. They gather resources and build their capacity. They have defenders. For ones formed before 1970, they have over half a century of inertia and history.

Even with changed rules, the number of Illinois local governments remains high. It will take a major sustained effort to reduce the number.