Forms of County Government in Illinois
The Illinois General Assembly, by statute, provides for three kinds of counties: counties under township organization, counties under a commission form, and counties under a county executive form of government.
The Illinois Constitution of 1848 allowed voters in each county to choose to establish township governments or a county commission form of government. Today, 85 of the 102 counties in Illinois operate under the township form of government. Township counties usually operate with standing committees. These committees study the particular problems that arise within their areas of responsibility and submit recommendations to the full board for action. A county board member can also hold the office of township supervisor.
The commission form of government is the oldest and most traditional county organizational structure. Under the commission form, the county governing body consists of an elected board composed of three (3) or five (5) commissioners who serve as the legislative body and also perform executive functions. No single administrator or executive oversees a county's operations under the commission form of government. Each year the commissioners select one of themselves as chairperson, most often alternating the designation.
There are currently 17 counties operating under the commission form of government in Illinois: Alexander, Calhoun, Edwards, Hardin, Johnson, Massac, Menard, Monroe, Morgan, Perry, Pope, Pulaski, Randolph, Scott, Union, Wabash and Williamson.
County Executive Form
A county which has a chief executive officer is considered a "home rule unit". A county-wide referendum is required to establish this plan. Home rule counties have broad authority to provide for local government issues. The advantage of this designation is that, except as limited by State law, home rule counties may exercise any power and perform any function relating to its government and affairs, including the power to regulate for the protection of the public health, safety, morals and welfare; to license; and to borrow money and levy taxes.
Cook County is the only home rule county in Illinois. Will County voters elected to go to a county executive form without home rule in 1988.
Here is a fact sheet expaining how County Boards are Elected.
How County Boards are Elected