Statutes are laws passed by state legislatures (state laws) and by the United States Congress (federal laws). Statutes are one of the primary sources of law in the United States (sometimes referred to as statutory law) and cover a wide variety of legal topics. Courts often rely on statutes to resolve legal disputes (lawsuits) by applying the relevant statutes to the particular set of factual circumstances underlying the dispute.

Courts generally seek the clear and plain meaning of a statute, and if the court finds a statute ambiguous or “ambiguous on its face” (looking only at the words as written) the court may attempt to determine what the legislature intended in enacting the statute—known as legislative intent.

Related statutes are sometimes compiled in groups and referred to as codes—such as the penal code, the family code, or the code of civil procedure. Statutes may be amended (changed) or repealed (eliminated) by the legislature or Congress or declared unconstitutional (and thus unenforceable) by a court.

In Illinois, as in other states, statutes are laws enacted by the state legislature, known as the Illinois General Assembly, and by the United States Congress at the federal level. These statutes encompass a broad range of legal areas and serve as a fundamental source of law, often guiding courts in resolving disputes by applying the relevant laws to the facts of each case. When interpreting statutes, Illinois courts strive to ascertain the plain meaning of the legislative text. If a statute is deemed ambiguous, courts may look into legislative history and intent to interpret the statute's meaning. Illinois statutes are organized into compiled codes for ease of reference, such as the Illinois Compiled Statutes (ILCS), which include various codes like the Criminal Code, the Civil Procedure Code, and the Family Code. Statutes can be modified or repealed by the legislature and may also be subject to judicial review, where they can be struck down if found to be unconstitutional.