National Law is the set of laws that exist in a particular nation (State). The term national law can refer to either the rules imposed by a government or, in States with a common law tradition, the decisions made by judges.

The national law of the United States, commonly known as federal law or US law, consists of statutes, regulations, and court decisions created by the Congress of the United States and signed into effect by the President of the United States. Federal law is also governed by the Constitution of the United States and, to some extent, by the doctrine of separation of powers under which the federal government is given specific, limited powers.

Article VI, Paragraph 2 of the United States Constitution is known as the Supremacy Clause and establishes that the laws of the United States take precedence over state law. This includes the US Constitution and laws enacted by Congress.

The legal system in the United States is based on principles such as equality before the law, due process, freedom of speech and religion, and the right to privacy. These principles are enforceable by the courts, which can be used to protect rights that may be infringed upon by the majority or by certain individuals. The Supreme Court, for example, has upheld the right of employees to organize and bargain collectively. The federal courts have a significant role to play in protecting these principles and protecting individual rights.