List of national legal systems
Common law is currently in practice in Ireland, most of the United Kingdom (England and Wales and Northern Ireland), Australia, New Zealand, Bangladesh, India (excluding Goa), Pakistan, South Africa, Canada (excluding Quebec), Hong Kong, the United States (on a state level excluding Louisiana), and many other places. In addition to these countries, several others have adapted the common law system into a mixed system. For example, Nigeria operates largely on a common law system, but incorporates religious law.
Federal common law
Federal common law is a term of United States law used to describe common law that is developed by the federal courts, instead of by the courts of the various states. The United States is the only country to combine the creation of common law doctrines with a complete federalism, wherein the national supreme court has virtually no power to review state court decisions to determine whether the state courts have followed state laws. The High Court of Australia is sometimes said to have federal common law, but because all state and territorial courts are directly appealable to the High Court, this is indistinguishable from a general common law. In contrast, the United States Supreme Court has effectively barred the creation of federal common law in areas traditionally under the authority of state courts. Nevertheless, there are several areas where federal common law continues to govern.