Law of Illinois

The law of Illinois consists of several levels, including constitutional, statutory, and regulatory law, as well as case law and local law. The Illinois Compiled Statutes (ILCS) form the general statutory law.

The Constitution of Illinois is the foremost source of state law. Legislation is enacted by the Illinois General Assembly, published in the Laws of Illinois, and codified in the Illinois Compiled Statutes (ILCS). State agencies publish regulations (sometimes called administrative law) in the Illinois Register, which are in turn codified in the Illinois Administrative Code. Illinois's legal system is based on common law, which is interpreted by case law through the decisions of the Supreme Court and the Appellate Court, which are published on the website of the Supreme Court. Counties, townships, cities, and villages may also promulgate local ordinances. In addition, there are also several sources of persuasive authority, which are not binding authority but are useful to lawyers and judges insofar as they help to clarify the current state of the law.

The Constitution of Illinois is the foundation of the government of Illinois and vests the legislative power of the state in the Illinois General Assembly. The Illinois Constitution in turn is subordinate only to the Constitution of the United States, which is the supreme law of the land.

Pursuant to the state constitution, the Illinois General Assembly has enacted legislation. These legislative acts are published in the official Laws of Illinois and are called "session laws". The Illinois Compiled Statutes (ILCS) are the codified statutes of a general and permanent nature.

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