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 form the general statutory law.
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 are the codified statutes of a general and permanent nature. The Illinois Legislative Reference Bureau makes additions, deletions, and changes to ILCS. There is no official version of the ILCS. There are several unofficial versions: Illinois State Bar Association's/West's Illinois Compiled Statutes, West's Smith–Hurd Illinois Compiled Statutes Annotated, and LexisNexis's Illinois Compiled Statutes Annotated.
Administrative law
Pursuant to certain statutes, state agencies have promulgated regulations. The regulations are codified in the Illinois Administrative Code. The Illinois Register is the weekly publication containing proposed and adopted rules. There also exist administrative lawdecisions. Both the Illinois Administrative Code and Illinois Register are maintained by the Illinois Secretary of State. The Illinois Administrative Code was last printed in 1996. The General Assembly's Joint Committee on Administrative Rules also publishes online versions. The Flinn Report is a weekly newsletter published by the Joint Committee meant to inform and educate Illinois citizens about current rulemaking activity.
Case law
Illinois's legal system is based on common law, which is interpreted by case law through the decisions of the Supreme Court of Illinois and the Illinois Appellate Court. The official reporter for opinions of the Supreme Court and the Appellate Court are published on the website of the Illinois Supreme Court using a public domaincase citation. There are also unofficial sources such as West's Illinois Decisions with opinions since 1886. Illinois Appellate Court decisions from before 1935 are not binding. Illinois Circuit Court decisions are not published, but jury verdicts and settlements are published in the monthly Illinois Jury Verdict Reporter, with regular updates from the Chicago Daily Law Bulletin, and the weekly Cook County Jury Verdict Reporter. Decisions of the Illinois Court of Claims are published in the Court of Claims Reports. The Illinois Digest is an indexed compilation of summaries of opinions, or digest. The opinions of the Supreme Court and Appellate Court had been published in the Illinois Reports and Illinois Appellate Court Reports, respectively, from 1831-2011; according to the University of Chicago Library, since 1819 and 1877, respectively. Illinois Circuit Court decisions were published from 1907–1909.
Local ordinances
Illinois counties, townships, cities, and villages may promulgate local ordinances. The Government of Chicago operates as a special charter municipality. The Journal of the Proceedings of the City Council of the City of Chicago is the official publication of the acts of the Chicago City Council, and the Municipal Code of Chicago is the codification of its local ordinances of a general and permanent nature. Shepard's Illinois Citations includes judicial interpretations of local ordinances.
Other
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. Illinois Jurisprudence and Illinois Law and Practice are two major legal encyclopedias. The Illinois Institute for Continuing Legal Education also publishes guides for continuing legal education.
