Another classification of laws is based on the scope of the laws, that is, on the parties to whom they apply. This classification includes public and private law.

Private law governs the relationship between private citizens. Disputes may involve property, contracts, negligence, wills, and any number of other matters. Occasionally, as in marriage and divorce, the state may be involved indirectly, but, as the state is not itself a litigant, the matter remains one of private law.

Public law is a branch of law concerned with regulating the relations of individuals among themselves and with the government as well as the organization and conduct of government itself. Public-law disputes involve the state or its agencies in a direct manner. Usually the state is a litigant; it is often the plaintiff, the party bringing the suit to court. Examples of public law are municipal law, township law, criminal law, admiralty law, securities law, social security law, and aviation law.

When individual laws are referred to, however, there is a different kind of distinction between public and private laws. Specifically, a private law is a law that affects only selected individuals or localities, while a public law affects the welfare of the whole governed unit. A private law provides a kind of exception to the public rule.

Administrative law has become a major part of public law. Administrative law comprises the rules and regulations framed and enforced by a federal or state administrative agency as well as any rulings that the agency makes. Administrative bodies, while primarily executive in nature, may be delegated some legislative or judicial authority. For example, the Federal Aviation Administration not only issues regulations for air transportation but also adjudicates some disputes between airlines and their customers. The rules and regulations created by the federal administrative agencies are first published chronologically in the Federal Register (Fed. Reg.) and then later organized by subject in the Code of Federal Regulations (C.F.R.). See Important Agencies for information on some of the federal agencies.

State and local governments also have administrative agencies that issue rules, regulations, and rulings. They may be a part of an executive department of the state government or they may be independent entities. These agencies tend to regulate areas not preempted by federal agencies, but they may also be found in fields subject to both federal and state regulation. State administrative agencies often have jurisdiction over these areas: unemployment and workers’ compensation, taxation, education, motor vehicles, zoning, and health and safety. States publish their administrative law in compilations similar to the Federal Register and Code of Federal Regulations.