Illinois State Government: Structure & Operation

Instructor: Christopher Muscato

Chris has a master's degree in history and teaches at the University of Northern Colorado.

Every US state has its own government, and in this lesson we're going to see what Illinois' is like, including the various branches of this government and their respective responsibilities.


When people talk about the state of Illinois, they'll often comment on Chicago, but that's about it. Not everyone knows this, but there is more to Illinois than just this single (admittedly awesome) city. About 80% of the state is farmland, more of which goes to pumpkins than you might think. In fact, 85% of America's packaged pumpkin comes from Morton, IL. Illinois is also the birthplace of Twinkies (River Forest, IL), the first use of electric street lightings (Aurora, IL), and the ice cream sundae (Evanston, IL).

Flag of Illinois

Overseeing all of this is Illinois' state government, which passes laws, oversees administration, and keeps the state running. This government takes its authority from the Constitution of Illinois, adopted in 1970 as the fourth constitution of the state. This document outlines the powers and responsibilities of the government, and gives it enough power to oversee everything in the state.

The Executive Branch

All 50 US states maintain their own government, and all 50 are set up like the federal government, including Illinois. This means that Illinois' state government is broken into three branches, each of which contributes to the law in different ways. These branches are the executive, legislative, and judicial. All of them are based in state capital of Springfield.

The state capitol building in Springfield houses the office of the Governor and the state legislature

Let's start with the executive branch. The executive branch implements and enforces the laws of the state. At its head is the Governor, the elected official who acts as the state's chief executive. The governor serves a term of four years, and can be re-elected indefinitely. In fact, Illinois is one of a handful of states with no term limits on governors.

The Governor is assisted by five other elected leaders, the Lieutenant Governor, the Attorney General, the Secretary of State, the Treasurer, and the Comptroller. For those who are unfamiliar with the term, a comptroller is a public official who maintains the state's financial accounts and oversees the money going out and coming in. Together, the members of the executive branch oversee numerous state agencies and departments that handle everything from land management to consumer protection to preventing government fraud and corruption.

The Legislative Branch

The executive branch enacts and enforces the laws, but where do they come from? Illinois' state laws are created by the legislative branch. In the US federal government, the legislature is known as Congress. In Illinois, this body is called the Illinois General Assembly.

The General Assembly is the lawmaking organ of the state government, and like Congress it's bicameral, which means it has two houses. The Senate is composed of 59 members with four-year terms (except during special times within the decade when census data is recalculated and some are elected for two-year terms). The House of Representatives is the second house of the General Assembly, with 118 members who serve for two-year terms. Together, these houses debate, amend, and create laws for the people of Illinois.

The James R. Thompson Center of Chicago houses many government offices for the state

The Judicial Branch

The last branch of Illinois' state government is the judiciary, which is the court system. The judiciary is responsible for interpreting the law and state constitution, and ensuring that it is being upheld correctly. The highest court of the state is the Illinois Supreme Court, which functions very similarly to the United States Supreme Court. The Illinois Supreme Court can challenge the ruling of lower courts, and has the power to declare state laws or policies and unconstitutional. It is also responsible for determining how US federal laws and policies interact with Illinois' states laws and constitution.

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