Territorial jurisdiction describes the geographic area within which a court, tribunal or public authority may lawfully exercise its powers, hear a case or enforce orders. It determines whether a legal matter is properly brought before a particular court system, and whether that court can bind the parties or property concerned. In the UK and Ireland, the concept underpins rules on allocation of business between courts (for example, the division between the courts of England and Wales, Scotland and Northern Ireland, and between those and the courts of Ireland), as well as international jurisdiction in cross‑border disputes. It is reflected in legislation and procedural rules (such as rules on service out of the jurisdiction, forum conveniens/forum non conveniens, and recognition and enforcement of foreign judgments), and developed further through case law. Territorial jurisdiction is distinct from subject-matter jurisdiction and personal jurisdiction, though they often overlap in practice. It is central to litigation strategy, choice of court, conflict of laws, criminal prosecution where conduct or effects span borders, and public law challenges to decisions of UK and Irish authorities acting outside, or at the edge of, their lawful territorial competence.