Article III extends federal judicial power to "all Cases of admiralty and maritime Jurisdiction," giving federal courts exclusive authority over shipping disputes, maritime contracts, and navigational matters. The 1789 Judiciary Act granted district courts this jurisdiction to ensure uniform federal rules replaced the chaotic patchwork of state admiralty procedures under the Articles of Confederation.
The Supreme Court has ruled that admiralty jurisdiction covers all navigable public waters—rivers, lakes, and oceans—regardless of tides or saltwater. Federal admiralty judges conduct trials without juries and apply general maritime law rather than common law. The Framers wanted federal courts handling these cases because maritime disputes often involve foreign ships and international trade, where inconsistent state rulings could damage the nation''s foreign policy. The "saving to suitors clause" allows plaintiffs to sue individuals in state courts for maritime torts and contracts, but claims against vessels themselves must go to federal court.