There are two types of townships-civil and congressional.
Civil townships are the political subdivisions and government units to which we generally refer as today’s townships. They have been established according to geographical boundaries such as creeks, rivers and lakes.
Congressional townships consist of a rectangular, grid-like system for the United States. Since the system was established without boundary considerations, congressional townships often overlap political jurisdictions and even states.
The congressional township is used throughout Illinois for property assessments and tax purposes. Townships are approximately six miles square.
Twenty of the 1,433 townships in Illinois have coterminous boundaries with a municipality. Most of these coterminous political subdivisions were organized since 1911 and are governed by the city council, which also serves as the township board of trustees. In the case of the coterminous governing bodies, the general assistance functions are still maintained by the township supervisor.