Judicial notice is a court’s acceptance of a well-known and indisputable fact without requiring the party relying on the fact to prove it. The doctrine of judicial notice is one of common sense, and is based on the theory that where a fact is well-known in the community—or its existence is easily determined from sources that cannot be reasonably questioned—it would not be a good use of judicial time and resources to require formal proof of the fact in court. A court may take judicial notice of both facts and laws.

In Ohio, the concept of judicial notice is governed by the Ohio Rules of Evidence, specifically Rule 201. This rule allows Ohio courts to take judicial notice of certain facts that are not subject to reasonable dispute because they are either (1) generally known within the territorial jurisdiction of the trial court or (2) capable of accurate and ready determination by sources whose accuracy cannot reasonably be questioned. This includes both adjudicative facts and law. Adjudicative facts are those facts that are relevant to the issue in a case, while laws include statutes, administrative rules, and court decisions. The court can take judicial notice on its own or upon request by a party. Once a court takes judicial notice of a fact, it is accepted as conclusive in civil cases. In criminal cases, however, the jury is instructed that it may, but is not required to, accept as conclusive any judicially noticed fact. The doctrine simplifies proceedings by avoiding the need to prove facts that are already commonly known or easily verifiable.