Unwritten Law Law and Legal Definition

Unwritten law refers to the law based upon custom, usage, and judicial decisions. It is distinguished from the enactments of a legislature, orders or decrees in writing. Although an unwritten law is not enacted in the form of statute or ordinance, it has got legal sanction. An unwritten law need not be expressly evidenced in court decisions, but may be collected, gathered or implied there from under statute.

In In re Estate of Spoya, 129 Mont. 83 (Mont. 1955), the court held that unwritten law is the law not promulgated and recorded, but which is, nevertheless, observed and administered in the courts of the country. It has no certain repository, but is collected from the reports of the decisions of the courts and treatises of learned men.