Public international law includes, but is not limited to: the United Nations human rights treaties, maritime law (law of the sea), international criminal law, international norms pertaining to nationality and citizenship, the Geneva Conventions and other sources of international humanitarian law (IHL). A common classification of public-law fields is fourfold: (1) constitutional, (2) administrative, (3) public international and (4) international human rights law.^[1]

Public international law concerns the structure and conduct of states and intergovernmental organizations. To a lesser degree, international law also may affect multinational corporations and individuals, an impact increasingly evolving beyond domestic legal interpretation and enforcement. Public international law has increased greatly in use and importance over the last century, due all to the increase in adjudicating disputes involving global trade, armed conflict, environmental degradation and human rights violations.

Public international law is sometimes called the law of nations. It should not be confused with private international law, which is concerned with the resolution of conflict of laws.