Districts in Illinois come in six main varieties: judicial, congressional, state legislative, school, township, and special purpose. Illinois has more units of local government than any other state, and a single home can sit inside a dozen or more of these districts at once. Each layer carries its own boundaries, its own elected officials, and in most cases its own authority to levy property taxes. That is why a single address in Illinois can appear on so many ballots and generate such a long tax bill.
Judicial Districts and Circuits
The Illinois Constitution divides the state into five judicial districts for electing Supreme Court and Appellate Court judges.1Illinois General Assembly. Illinois Constitution – Article VI Cook County stands alone as the First Judicial District. The other 101 counties are spread across the Second through Fifth Districts. These lines went untouched from 1964 until Public Act 102-0011 took effect on January 1, 2022, realigning the districts to reflect decades of population shifts.2Illinois Courts. Illinois Judicial Redistricting
The Supreme Court has seven justices. Three come from the First District and one from each of the other four.1Illinois General Assembly. Illinois Constitution – Article VI A Supreme Court or Appellate Court judge seeking a new term after the initial one must win a retention election with at least 60 percent of the vote.
Trial courts work on a different map. Illinois operates 25 judicial circuits. The Constitution requires Cook County to form its own circuit, while the General Assembly draws the rest, which can contain anywhere from one to twelve counties.3Illinois Courts. The Circuit Court of Illinois Seven circuits are single-county: Cook, DuPage, Kane, Lake, McHenry, St. Clair, and Will. Circuit courts handle the cases most people actually encounter, including criminal trials, divorces, landlord-tenant disputes, personal injury suits, and small claims. Each circuit’s judges elect a Chief Judge from among themselves, who holds broad administrative authority over scheduling and courtroom assignments.1Illinois General Assembly. Illinois Constitution – Article VI
The distinction trips people up: the five districts matter for appellate and Supreme Court elections, and the 25 circuits matter for your local trial court.
Congressional Districts
Illinois currently sends 17 members to the U.S. House of Representatives, down from 18 before the 2020 census.4U.S. Census Bureau. Apportionment of Seats in the U.S. House of Representatives Federal law requires any state with more than one representative to elect them from single-member districts rather than at large.5Office of the Law Revision Counsel. 2 U.S. Code 2c – Number of Congressional Districts The General Assembly draws those boundaries after each decennial census, and the current map reflects the population decline that cost the state a seat. Districts must contain roughly equal populations to satisfy one-person-one-vote.
State Legislative and Representative Districts
The Illinois General Assembly runs on a nested system. The state is divided into 59 Legislative Districts, each electing one state senator, and those are subdivided into 118 Representative Districts, each electing one state representative.6Illinois General Assembly. Illinois Constitution – Article IV Every senate district contains exactly two house districts, so your state senator always overlaps with one of your two potential representatives.
Senate terms rotate on a staggered cycle so that roughly a third of the Senate is up for election at any given time. State representatives serve simple two-year terms. Boundaries are redrawn every ten years following the federal census, and the Illinois Constitution requires districts to be compact, contiguous, and substantially equal in population. If the legislature deadlocks on a map, the process escalates to a bipartisan commission.
School Districts
Illinois has roughly 850 school districts, and they operate independently of city, village, and county governments. The Illinois School Code recognizes three types: elementary districts for younger grades, high school districts for upper grades, and unit districts that cover kindergarten through twelfth. In many places an elementary district and a high school district cover the same geography, each with its own elected board and its own budget.
Every school district is an independent taxing body with authority to levy property taxes for instruction, buildings, and operations. Local school boards set the levy, hire the superintendent, and shape academic policy. Boundaries are generally fixed but can be altered through consolidation or detachment petitions filed under the School Code.
Evidence-Based Funding
Since 2017, the state has distributed the bulk of its education aid through the Evidence-Based Funding model, which replaced the older formula that critics said shortchanged the poorest districts.7Illinois State Board of Education. Evidence-Based Funding The formula sets an adequacy target for each district based on enrollment, demographics, and local costs, then measures how much of that target local revenue already covers. Districts are sorted into four tiers. Tier 1 districts fall below 75.6 percent of their adequacy target for fiscal year 2026 and receive the largest share of new state dollars; Tier 4 districts meet or exceed 100 percent and receive the least.
Township Districts
Townships exist in 85 of the state’s 102 counties. The other 17 counties use a commission form of government. Illinois has over 1,400 townships, and they handle a mixed set of duties: property tax assessment, road and bridge maintenance, general assistance for residents in financial hardship, and in some areas zoning, youth and senior services, or even police and fire protection.
Each township is governed by an elected board of a supervisor and four trustees, and many townships also elect separate highway commissioners, assessors, and clerks. Townships can levy property taxes and issue bonds. Their duties overlap in places with those of municipalities and counties, which is why they come up often in debates over consolidating local government.
Special Purpose Districts
Special purpose districts deliver a single type of service. The list is long and includes park districts, library districts, fire protection districts, forest preserve districts, sanitary districts, mosquito abatement districts, cemetery districts, and airport authorities. The statutory framework for most of them sits in Chapter 70 of the Illinois Compiled Statutes, with each district type governed by its own act.8Illinois General Assembly. Illinois Compiled Statutes – Chapter Special Districts
Most special districts can levy property taxes and issue bonds, though not all can. Exposition authorities, for example, are specifically prohibited from imposing taxes.9Illinois General Assembly. 70 ILCS 1600 – Exposition Authority Incorporation Act Each district that does have taxing power appears as a separate line on your property tax bill.
Sanitary districts show how focused these entities can be. Under the Sanitary District Act of 1917, a sanitary district can build and maintain sewage systems, treat wastewater, and charge connection fees to new users, but it cannot operate waterworks or extend service to individual residences.10Illinois General Assembly. Sanitary District Act of 1917 – Trustees; Powers Narrow mandate, direct accountability. That is the logic behind special districts.
How the Layers Add Up on Your Property Tax Bill
The practical result of all these overlapping districts shows up on property tax bills. A single home sits within a county, possibly a township, a municipality, one or more school districts, a community college district, and often several special districts for parks, libraries, and fire protection. Each sets its own levy, and the county clerk adds them together to produce the aggregate tax rate for your property.11Illinois Department of Revenue. The Illinois Property Tax System
The Property Tax Extension Limitation Law caps how much most districts can grow their levies each year. The limit is tied to the Consumer Price Index or 5 percent, whichever is lower.12Illinois Department of Revenue. Property Tax Extension Limitation Law (PTELL) For taxes paid in 2026, that cap is 2.90 percent.13Illinois Department of Revenue. Property Tax – History of CPIs Used for PTELL The cap applies to the total extension a district collects, not to an individual bill, so new construction and rising property values can still push a bill higher even when a district stays within the limit.
Illinois consistently ranks among the states with the highest property taxes, and the sheer number of independent taxing districts is a major reason. Each levy may look modest in isolation, but a dozen stacked together can produce effective rates above 3 or even 4 percent of a home’s market value in some areas. Periodic efforts to consolidate or eliminate overlapping districts have gained political traction but rarely produce dramatic reductions, because each district has a constituency that benefits from the services it funds.